Proceedings of the Standing Senate Committee on
Social Affairs, Science and Technology
Issue 41 - Evidence - May 30, 2013
OTTAWA, Thursday, May 30, 2103
The Standing Senate Committee on Social Affairs, Science and Technology
met this day, at 10:28 a.m., to examine the subject matter of Bill C-314, An
Act respecting the awareness of screening among women with dense breast
Senator Kelvin Kenneth Ogilvie (Chair) in the chair.
The Chair: Honourable senators, our second witness is not here at
the moment, but with your agreement we will begin and welcome her to the
meeting as soon as she does arrive. We were scheduling her presentation to
be second in any event.
Welcome to the Standing Senate Committee on Social Affairs, Science and
My name is Kelvin Ogilvie, a senator from Nova Scotia and chair of the
committee. I would now invite my colleagues to introduce themselves.
Senator Seidman: Judith Seidman from Montreal, Quebec.
Senator Martin: Yonah Martin, British Columbia.
Senator Seth: Asha Seth, Ontario.
Senator Eaton: Nicky Eaton, Ontario.
Senator Enverga: Tobias Enverga from Ontario.
Senator Cordy: I am Jane Cordy; I am a senator from Nova Scotia.
Senator Dyck: I am Lillian Dyck, a senator from Saskatchewan.
Senator Eggleton: Art Eggleton, senator from Toronto and deputy
chair of this committee.
The Chair: Thank you, honourable senators.
I will welcome the witnesses as I introduce them to make their
presentation. I remind colleagues that we have a very tight meeting. We have
two sessions. The first is scheduled to end in exactly one hour. The second
will end one hour following that. I want to remind you that we will stay as
a committee for approximately half an hour or less following the end of this
meeting to deal with instructions to the analysts. That was on the agenda as
was sent out. Is that agreed?
Hon. Senators: Agreed.
The Chair: Today we are continuing our study of the subject matter
of Bill C-314, and we are very pleased today to welcome, from the Canadian
Association of Radiologists, Dr. Jacques Lévesque, President; and Dr. Jean
Seely, Working Group Member, dealing with CAR Practice Guidelines Breast
Welcome. I understand that Dr. Lévesque will be making the presentation.
Dr. Jacques Lévesque, President, Canadian Association of Radiologists:
Mr. Chair, ladies and gentlemen, committee members, the Canadian
Association of Radiologists (CAR) is the national specialty society for
approximately 2,500 radiologists. As the physician experts in medical
imaging, we are dedicated to promoting patient safety in medical imaging.
We are pleased that the government views breast health as a topic
requiring a national approach. In doing so, it gives us the opportunity to
be here to provide comment on the Breast Density Awareness Act.
The CAR has operated an accreditation program for screening and
diagnostic mammography centres for 20 years. The program ensures that only
qualified medical personnel perform and interpret mammograms and that
dedicated mammography equipment remains optimally operational.
The CAR also produces practice guidelines for healthcare providers. Its
CAR Practice Guidelines and Technical Standards for Breast Imaging and
Intervention will be released shortly. We believe that annual screening
with mammography beginning at age 40 has been scientifically proven to
significantly decrease breast cancer mortality.
Accurate and accessible information is extremely important for patients
and their doctors. The CAR Standard for Communication of Diagnostic
Imaging Findings states that the radiologist report, which transmits the
imaging information from the radiologist to the referring physician, should
identify factors that can limit the sensitivity and specificity of the
examination, including patient anatomy such as dense breast pattern. A
referring physician who is alerted to a patient's breast density should only
use the information together with other pertinent patient medical
information, such as the patient's cancer history, family history of breast
cancer, past surgical history, to decide if additional breast cancer risk
assessment and/or supplemental screening are necessary.
Although dense breast pattern has been shown to lower the sensitivity of
mammography, which is lower now with digital mammography, there is
insufficient consensus in literature to indicate that, on its own, it
warrants supplemental screening or diagnostic procedures, such as ultrasound
or magnetic resonance imaging. We strongly question, however, how patients
may interpret the specifics of the information about breast density and
whether it will be of benefit or lead to confusion or other unintended
consequences for the patient, which I will describe.
In addition, if it leads to unnecessary testing, non-scientific
approaches to screening, or a significant increase in the number of benign
breast biopsies, it has not been a positive contribution to patient care. We
would support the Canadian Breast Cancer Screening Initiative (CBCSI)
position that it is premature to require screening programs to
systematically inform women of their breast density.
A number of jurisdictions already indicate in the screening report that
mammography does not detect all cancers. Patients are already becoming aware
of this fact.
In conclusion, radiologists are encouraged to continue to use standard
classification of breast tissue density on mammography reports, in
accordance with the ACR BI-RADS lexicon, and CAR guidelines.
Given that there is currently no evidence that additional screening with
breast ultrasound or MRI reduces breast cancer mortality in women with dense
breast tissue, and a lack of consensus on what risk this represents to the
patient, the false positive diagnoses and the high number of biopsies, we
seek to avoid increasing confusion and anxiety amongst women regarding the
fear of breast cancer.
We would be happy to answer any questions you may have. Dr. Seely is an
MRI expert, among other things.
The Chair: Thank you very much.
Honourable senators, could I get your agreement that if Dr. Duchesne
arrives we would let the answer to a question already posed finish and then
immediately invite her to present? Are you agreeable to that procedure?
Hon. Senators: Agreed.
The Chair: I will now open the questioning, beginning with Senator
Eaton, to be followed by Senator Seidman, to be followed by Senator
Senator Eaton: May I quote you, Dr. Lévesque? "CBCSI's position
[is] that it is premature to require screening programs to systematically
inform women of their breast density." Could you elaborate on that
Dr. Lévesque: If you systematically indicate on the copy of the
mammography report sent to the patient that she has dense breast tissue,
what will she do? She will go on the Internet and find all sorts of
We believe that awareness must primarily come from the attending
physician and the referring physician. I may get a screening report that
shows dense breast tissue. We are screening experts. Not all cases require
additional investigation. Often, we have previous reports that we can use
for comparison purposes. If I still see that the mammary parenchyma is
really distorted and that it is outside the range of being able to properly
do the screening mammography, I will mention in my report to the attending
physician that the mammography is restrictive, and that either a clinical
examination of both breasts or other complementary examinations should be
Some women will probably be able to properly assess what that means. For
most people, we will be increasing the risk of anxiety and put them in a
situation where they might twist the doctor's arm to order an ultrasound or
MRI. But our current health care system does not have the resources to
systematically perform ultrasounds on all women with very dense breasts,
which represent 30 per cent of the breast cancer screening volume.
Senator Eaton: If I could sum up, you are saying that unless you
pick up something very extraordinary, you will refer it to the doctor that
is looking after her and it is up to the doctor to judge whether he should
discuss it with the patient.
Dr. Lévesque: I think it is a good practice right now.
Dr. Jean Seely, Working Group Member: CAR Practice Guidelines Breast
Imaging, Canadian Association of Radiologists: If I could speak to the
assessment of risk, I think one of the more important risk factors is family
history. Family physicians are often very aware of what that family history
would be. If they have one, two or more than two first-degree family members
with breast cancer, that would be an indication that they are at a higher
relationship for additional screening. That risk factor would potentially be
much more significant than the ones we were talking about here with breast
The Chair: As per our agreement, when Dr. Nathalie Duchesne
arrived we said that we would finish the response to a question on the table
and then invite her to present. I should note for the audience that Dr.
Duchesne is the associate of the Clinique radiologique Audet and is a breast
Please make your presentation.
Dr. Nathalie Duchesne, Breast Radiologist, Clinique radiologique
Audet: We are here this morning basically for different reasons, but one
reason bringing us together is that we all know if we find breast cancer
when it is very small that we can improve the survival of the patient.
"Small" means that it is smaller than one centimetre. If we find breast
cancer when it is smaller than one centimetre, the survival rate is up to 97
and 100 per cent over 15 years. This was published in 1999. We started
breast cancer screening in 1990s in Canada in order to decrease the
mortality associated with breast cancer.
Now, if you look at Canadian cancer statistics, we see that we have
observed a decrease in the mortality associated with breast cancer, but over
the past 10 years, it has been slowing down. This decrease is, some say, at
2 per cent per year, but if you look at the numbers it is not really at 2
per cent. Perhaps we should wonder why, since there has been an amazing
improvement in the mammography over the past 20 and 10 years.
I am sure that you have had other experts showing you images, the
difference between the film mammography and the digital mammography. The
differences are amazing and one should wonder why, with these big
improvements in the technology, we cannot decrease the mortality more than
this. Why are we still dealing with stages that are high in Canada? We are
not in Timbuktu. Why do we not find all cancers when they are smaller than
one centimetre? Why are Canadian women dying of breast cancer in a country
with a screening program?
It is because we have not dealt with something that is a risk factor that
no one can control. It is not about smoking; we can stop smoking. Obesity is
a risk factor; we can stop eating. However, at first we did not know that
breast density was a risk factor and now we know it is and we cannot control
it. You have dense breasts or you do not. There has been nothing done so far
for the breast density risk factor. That is why the companies and
researchers that you will hear have worked very hard on how we can perhaps
decrease breast density. We know these days that maybe vitamin D is the
answer, but until we know for sure we need to find the cancer in those women
with dense breasts.
Two or three modes of imaging have demonstrated that they can help, can
be adjunct to mammography. One is MRI, but it is very expensive. It is not
at every street corner in Canada. It requires an injection, and although it
is very sensitive, it is not very specific. That is why we only do screening
with MRI for high-risk breast cancer patients.
However, two other modalities are showing that they can find breast
cancer smaller than one centimetre and one is definitely tomosynthesis. The
reason it works on thousands of women going towards this tendency, but
definitely the breast ultrasound. As I came in, I heard Dr. Lévesque. We all
agree, as radiologists for the past 30 years, that we know we find breast
cancers with breast ultrasound that we cannot find with mammography simply
because breast cancer is dark in an ultrasound and it is over white breast
parenchyma. That is why we can detect it easier.
Over the past 30 years we wondered how to use breast ultrasound as a
screening tool and could not figure out how because it is operator dependent
and reader dependent. Three companies on the market now have developed other
breast ultrasounds that seem to be a solution to decrease operator
dependency. However, we still have reader dependency. With ultrasound used
as a screening, we are now finding three times the cancers. We have tripled
the detection of cancers smaller than 1 centimetre, and that has been
demonstrated by different groups all over the world, in Europe as well as in
Having said that, we have the tools, but a fool with a tool is still a
fool. Yes, with Bill C-314 we have the capacity to tell women they have
dense breasts and therefore we can do an extra test such as ultrasound,
tomosynthesis or maybe an MRI.
However, what we need with this law is the ability. Unfortunately, in
Canada the system is not well organized to investigate breasts. If we tell
the women they have dense breasts, we will need to tell them where to go. We
have a problem with the resources, the expertise. I am not saying we do not
have the experts, but the experts are not well organized, let us put it that
Expertise in breasts is not encouraged for different political, economic
and legal reasons, contrary to other countries where expertise in breasts is
There are also people saying that it is not worth detecting breast cancer
in dense breasts because most of the time those dense breasts are found in
young women 40 to 49 years old. Should we screen the 40 to 49 year-old
women? I have slides here demonstrating that if you look at the costs per
lives saved in 40 to 49 year-olds with dense breast, the cost per lives
saved is more than 100 times less than the sprinklers in this room. No one
ever argued about those sprinklers in the law. No one ever argued about
anti-seismic construction. The cost of lives saved is $1 million more than
the cost of screening for 40 to 49 year-olds.
There is a problem with lobbying in Canada for women with dense breasts,
and there is a problem with reorienting our resources — it is not that we do
not have them. We should use this bill as a tool. Certain paragraphs in the
bill will help with dissemination of information and will help the provinces
to organize further tests. Let us not wait for another bill that will give
more federal jurisdiction to the provinces to organize for the health of
breasts because it will take years. Meanwhile, women are searching the
Internet and learning about breast density and know that there is something
going on. Let us use this bill and one of the paragraphs in the bill to help
Canada develop the resources for the provinces to deal with organizing the
Senator Seidman: A recent study in August 2012 shows that breast
cancer patients with dense breasts were no more likely to die than were
other patients in the study. Although dense breasts may increase the risk of
cancer, and that is controversial, women with dense breasts respond better
to treatment. Therefore, they are less at risk of dying from breast cancer.
Would you respond to that?
Dr. Seely: That is correct. I am aware of that study. There is
nothing about having dense breasts that increases your risk of dying from
breast cancer, as that study confirmed. Just because you have dense breasts
does not mean you will respond to treatment any differently or behave any
differently. It is only one factor to measure in the whole gamut of breast
cancer screening and diagnosis. Breast density is only one risk factor, and
there are many other very important risk factors. One of the points that we
wanted to make is that if we focus only on this, we may miss the opportunity
to focus on other risk factors that may be even more important, such as
family history and prior history of other breast diseases.
We recognize that breast density makes people very concerned. One of our
fears about this bill is that it will greatly increase the anxiety of women
without knowing really what to do. We offer screening breast ultrasound at
the Women's Breast Health Centre of The Ottawa Hospital. However, as Dr.
Duchesne mentioned, we have very limited availability of qualified
technologists' and radiologists' time to offer this in a massive way. Our
concern is that if we let women know about this density, one of the risk
factors, we will not have the opportunity to actually deal with it. We want
to minimize the anxiety when there is a great deal of anxiety about breast
cancer, which is always augmented by the media and by these bills. That is
why we are concerned if we mandate it.
Dr. Duchesne: I agree with Dr. Seely. However, I would add that
some risk factors can be controlled, while others cannot. For instance, we
cannot control the family risk, but we treat those patients differently. The
patients who have a family history of breast cancer have a mammogram every
year instead of every two years. Those who have very high- risk genes have
more thorough screening with regular MRIs and mammograms.
The study you are referring to shows that a person with dense breast
tissue, with a cancer of 1.2 centimetres, does not have a higher risk of
dying from the cancer than a person with fatty breast tissue with a cancer
of 1.2 centimetres. A 1.2-centimetre cancer in dense breasts is not more
dangerous than a 1.2-centimetre cancer in breasts that are not dense. The
outcome is the same. It all depends on hormone receptors, lymph nodes and a
whole host of things. A cancer is a cancer. The density of the parenchyma
prevents us from detecting it. Are we going to ignore the risk factors that
we cannot control by not telling patients that they have cancer in their
family history because they will be worried? The situation is the same. They
are at higher risk because of the family history and they are at higher risk
if they have higher breast density. We have the tools. We must not fall into
the trap of not providing a service because we are not well organized. Let
us get organized and let us take advantage of this bill to get organized.
Senator Eggleton: Let me start with the Canadian Association of
Radiologists. In your presentation, you paid a lot of attention to the
question of confusion and anxiety. I presume that when a radiologist
completes a mammogram, it is sent to the family physician. You said you are
concerned that many women will search online to figure out what it all means
and what they should do about it, but is not their first point of contact
their physician? Would the physician not have a responsibility to allay
Dr. Lévesque: That is a very good point. One of the main areas for
education is the referring physician. That is probably one of the key points
of the solution.
Dr. Duchesne mentioned the point of organization, which we will come back
to. It is what I do on a regular basis during my workday.
When I use the screening mammography and I see dense breasts, I will very
often advise the attending physician in my report that the breasts are in
fact dense, which limits the level of screening through mammography. It is
up to the attending physician then to do the follow-up. In my view, that is
the major, key role of the attending physician. He must then factor that in
with other aspects, such as previous examinations and the patient's history.
The real issue is the way health care is organized. Dr. Duchesne talked
about tomosynthesis and whole breast ultrasound. We are just starting to
implement this technology here. Very clear studies in Europe — and I was at
the conference organized by Dr. Duchesne — show that tomosynthesis will
significantly increase the ability to detect cancer in dense breasts. We are
just starting to implement the technology.
We have been using the breast ultrasound for a number of years. When I
examine a patient for a specific problem, as the doctor to my right said, in
relation to ultrasound screening, the time ratio is one to three for the
technologist and the radiologist. Even if we were to have all the mature
technology we need by tomorrow morning, we would need to find a way to
streamline everything and treat the right patients. Unfortunately, we do not
have the necessary technological infrastructure in Canada.
Whole breast ultrasound devices have not been approved by Health Canada
yet and we do not have enough technologists and radiologists to deal with
such a large number of patients.
When the screening programs were developed a few years ago, at least 15
years ago in Quebec — it was in 1998 — I was at the helm of the provincial
association to implement them and we have since come a long way in terms of
the skill of radiologists. With the CAR standards and guidelines, we used to
require radiologists to read a minimum of 500 mammograms a year. Now, most
radiologists read 1,000 or more. We have made significant technological
progress in terms of the availability of ultrasound devices in order to meet
the needs of the screening program.
However, we do not currently have the appropriate platform for
tomosynthesis or the validated and approved technology to be able to say
that, by tomorrow morning, we would be able to do it.
I agree with the fact that we need to find cancers that are smaller than
one centimeter, but we do not have the tools to do so overnight.
The work that you are currently doing is outstanding and it is certainly
a way to raise awareness and see if there is a way to have a national
program at some stage. Clearly, it is up to each province to decide; health
care falls under provincial jurisdiction. I can understand that the
provinces, before embarking on systematic programs, because it is a second
level of systematic breast cancer screening for patients like that, I will
not hide the fact that I do not think they have the financial resources to
Senator Eggleton: I was struck by Dr. Duchesne's phrase that a
fool with a new tool is still a fool. I take it you are saying there still
needs to be a lot more education and training. Could expand upon that? Why
do you think the bill helps or does not help in that regard?
Dr. Duchesne: This actually sort of continues along the same lines
as Dr. Lévesque's comments. First, I would like to say something about
patients' anxiety. Studies have shown that, when patients undergo additional
examinations, three months later, they say that they are not under
psychological stress. On the contrary, they are pleased they were examined
more. Patients are stronger than you think. Stress may not be all that it is
made out to be.
Now, where do we refer patients? As Dr. Lévesque said, we are at a second
level of screening. The first level is mammography and, if the mammography
shows dense or heterogeneous breasts, further investigation is required.
I would also like to make a small correction. Automated ultrasound has
been approved by Health Canada as an aid to mammography for screening, and
it is available across Canada through various companies, as is
tomosynthesis. There are little concerns with Health Canada, but once again,
this is used as an aid and does not replace mammography.
I did say that a fool with a tool is still a fool because people need to
understand what they are doing with these tools, and it is the organization,
the experts. At that second level, you need to have breast experts, experts
in breast imaging, who do this level of screening. We cannot ask every
radiologist to know everything about screening techniques.
As Dr. Seely said, ultrasound screening takes time. Whether it is
automated or not, you need to be used to doing a breast ultrasound. Therein
lies the problem: the experts are not organized, and the experts are spread
out throughout the groups of general radiologists. Canada certainly has to
take a leadership role in that area.
Take the United Kingdom, for example. Why does the UK program work? First
of all, screening is only read by experts. There are no general
radiologists, and only radiologists who are very specialized in breasts read
them. They must read a minimum of 5,000 results; in Sweden, it is 10,000.
Here, the number is around 1,000. They are also required to attend
interdisciplinary meetings; here, they are not. There is oversight and, if
you do not pass the test somewhere else, you no longer have the right to do
the screening. So women are protected. This level does not exist in Canada.
Therefore, passing the bill and being disorganized the way we are now will
not help. This bill should be used to organize the care.
The Chair: I would ask the witnesses to be more efficient in their
responses. I have certain senators left here. We want to get them in before
we end this at 11:30.
Senator Dyck: Dr. Lévesque and Dr. Seely, I was struck by what you
said about the risk factors that can put a woman at risk for developing
breast cancer. This bill addresses only one of those risk factors. Dr.
Duchesne, I believe you also said when a doctor is communicating with a
patient they should take all those risk factors into account.
Is there anything in place now, or that should be in place, that would
require the doctor to include all the other risk factors? This will say you
have to tell a woman about dense breast tissue. If it were a genetic factor
or occupational hazards, does the doctor have to communicate that and how
will this help then?
Dr. Seely: For all breast imaging exams, a questionnaire filled is
out by the patient. In that questionnaire she is asked about her risk
factors, such as how many family members have had breast cancer or whether
she has had prior biopsies, and most organized screening programs will have
access to that. The radiologist always accesses that information. When I
interpret a mammogram, which is screening, and I see that she has a strong
family history or she has had a previous breast biopsy that showed lobular
carcinoma in situ, then I will suggest in my report that she needs
additional screening. That would probably be with MRI if she qualifies for
that risk factor. If she has dense breasts I may add to that.
I wanted to clarify what Dr. Lévesque said about the whole breast
ultrasound. Some companies, and Dr. Duchesne works with one of the
companies, have two centres in Canada where they offer this automated whole
breast ultrasound. GE, which is a major vendor of automated whole breast
ultrasound, has not obtained Health Canada approval for its machines. It is
true there are some companies, but there is still quite limited access.
The Chair: For the record, it is important for us to note that
SonoCiné, of which I understand you are a shareholder, is an automated whole
breast ultrasound system.
Dr. Duchesne: That is why I declared already that I was a
shareholder and on the medical board of advisers, and I am also on the board
of CAR as a member.
The Chair: It is important with regard to disclosure that that is
on the record. Thank you.
Senator Seth: This is a never-ending discussion. It is quite
Dr. Lévesque, you have said:
In conclusion, radiologists are encouraged to continue to use
standard classification of breast tissue density on mammography reports,
in accordance with ACR BI-RADS lexicon, and CAR guidelines.
Could you explain what that means and how you grade? It will be very
interesting for the audience to know about this.
Dr. Lévesque: In fact, it is an international classification. When
you read screening you have this categorization, which will be updated. An
update is coming up but, as an example, I will say this is probably a fatty
breast, so it is category 1. After that it is a mid-1 and it is from 0 per
cent to 25 per cent, 25 per cent to 50 per cent, 50 per cent to 75 per cent,
and more than 75 per cent is considered the dense breast that we speak
about. It is where the discussion is right now. It is a guide for the
physician and it is a way to do standard reports. Most of the breast
screening in the world uses that, so physicians know what kind of breast it
Family physicians or OB/GYNs, as you are, receive a report that says it
is a dense breast. It is already a light which is open for the physicians
who are used to receiving these kinds of reports. As a screener, when I read
the mammography I see when there is some other abnormality or perhaps more
When I read the mammography, I put other elements in my comments, such as
the breast parenchyma is typical of fibrocystic dysplasia; there are a
number of nodular focal lesions — I do not use the term "mass" — that
really should be investigated by ultrasound. And it is the attending
physician who decides, the attending physician who has all the information.
Most of the time, the attending physicians do exactly what the
radiologists say. Because we are still the imaging experts and we are the
ones with the experience.
I would like to come back to the number of ultrasounds. Yes, there is a
consensus in the literature on the fact that radiologists who read more than
1,000 exams a year have a better positive value rating and a lower recall
rate. That is what we are using in several jurisdictions now. Canada is a
very large country, and it is also important to consider that we need to
serve remote regions. There is currently a screening program in 10
provinces, and there are a number of provinces that use mobile units
specifically for remote regions. Screenings are read by radiologists who are
very well trained in this.
Of course, the very specialized centres are there. Dr. Duchesne and Dr.
Seely work in very specialized centres, but I would like to point out that
we have a relatively good screening program in the various jurisdictions in
Senator Enverga: It was noted that you have three machines that
work well or do not work well enough and one is the breast ultrasound. If
you have a breast ultrasound and you have a good radiologist, will it be
enough? Will it be a one-stop shop for breast cancer detection?
Dr. Seely: Patients ask this all the time: "Can I just have an
ultrasound and not a mammogram?" That is the whole point. We always start
with the mammogram. I know you have heard presentations from Greg Doyle and
Christine Wilson and a number of experts with eight randomized control
trials showing the importance of screening mammography. It picks up the
calcifications, architectural changes on the breast; that is not just
density and we cannot pick it up any other way. We always start with a
mammogram. If we do additional testing to do an ultrasound, that is another
test on top of it. Then we have to do a biopsy to prove there is cancer.
I know you have heard that one of the big problems with screening
ultrasound is that the number of false positives is five times higher, so if
you have 100 women who have a screening mammogram, only 1 will have a
biopsy. If you have 100 women with a biopsy recommended by a mammogram, 40
will be cancer. If you have 100 women who have a screening ultrasound, 5
will be recommended for biopsy, and out of 100 women who have a biopsy
recommended on ultrasound, only 6 per cent will be positive. It is a six
times higher false positive biopsy rate with ultrasound and a five times
higher false positive recall rate for biopsy.
A lot of extra tests must be done. Not only do we have to do biopsies, we
have to do follow-ups. If we see something on these tests, we have to do
follow-ups. We take all of our time that we have dedicated to investigation
and we fill it up with a lot of these false positives and it clogs the
system. We have to be very careful about the other tests we add to a
population-based screening program and the effect on cost and on the
patients themselves and to our whole Canadian system.
Dr. Duchesne: I totally agree with Dr. Seely that ultrasound
cannot be used alone. It is really to be used as an adjunct to mammography,
especially because of microcalcification and the distortion that we do not
see well on ultrasound.
I want to ensure that you understand there are two types of ultrasound.
There is the inhale ultrasound and the automated. The automated was
developed so that we take less time. I am not saying that automated is the
only one. Regular ultrasound that is available in any hospital in any clinic
of Canada can be used as an adjunct to mammography by a good radiologist to
look for breast cancer.
Senator Enverga: It is about the fool and the tool. Do you mean
that a lot of our radiologists need more training or upgrading to use the
Dr. Duchesne: Of course, I have a different disclosure. Yes, it
was the automated whole breast ultrasound, but I am a woman and a breast
radiologist, so I am speaking as a specialist. That is all I do in life; I
do breasts. I am not a general radiologist. I believe in Mister Muffler for
cars. If I have a problem with my muffler I prefer to go see Mister Muffler
than a global mechanic. If I have a tumour in my head, I will go see a
neuroradiologist and no one questions that. If we go to this level that
there is probably something in the breast, I do not see why you would not go
see a breast radiologist.
I am not saying that we do not have breast radiologists in Canada; not at
all. We have them, and yes we definitely train them. We have fellowships in
breast radiology, et cetera. I am saying that they are diluted and not
encouraged to work in an organized centre in the whole of Canada. Dr.
Lévesque was talking about this vast country. The solution to that is
centralized reading. Women must have access to their mammography all over
the place, to their MRI, to their ultrasound, but the reading can be
centralized by specialists.
Senator Verner: This is a complex issue, and there are various
ways to address it. I must say that I am particularly proud to have you here
this morning because I have been a client of the breast disease centre at
the Saint-Sacrement hospital for 25 years. So I could not help but recommend
that you be invited here this morning.
Having said that, we are talking about the issue, and I have various
questions about dense breast tissue. I have no knowledge of medicine, but my
understanding is that it is a factor that should motivate or influence the
way cancer is detected, but it is not necessarily a factor that has an
impact on cancer treatment or the mortality risk. Is that correct?
Dr. Duchesne: That is correct.
Senator Verner: I often hear — and I say this as a woman — things
like: it is not a good idea to tell patients that they have dense breast
tissue because it creates anxiety. It is a little difficult for me, in 2013,
to hear something like that. Not to be mean, but I find it a little
maternalistic. In 2013, in the Internet age, I think any woman here around
the table — and the men, too — can get information on what is going on
I think I understand that it is perhaps better that a woman is not told
that she has dense breast tissue because problems arise at the next stage,
not in the woman's ability to comprehend a factor like that.
Dr. Duchesne: I agree with the fact that, in 2013, women are not
yet patients, and they have access to the Internet. Canadian women are just
as smart as American, European and other women. They see what is happening
with the legislation on the obligation to provide breast density. Women are
going to ask for it sooner or later. I think we need to use this bill to
determine what direction to take, once they have been told.
Dr. Seely: I agree with the fact that we have to treat patients
with respect and give them the opportunity to know. At the CAR, we recommend
having the density reported on every mammography, which is not done the same
way in all provinces. In Ontario, it is more or less 75 per cent, but in
other parts of Canada, it is done with the four existing categories.
Every patient has a right to a report. It is a universal principle in
medicine. This legislation does not exist in other countries, save for in
six American states. What will happen if this information is given to all
women? They will think they have to undergo more testing.
It is not that we do not want them to have the information, but what are
they going to do if the legislation stipulates that everyone must have a
Dr. Lévesque: My spouse is a pathologist. I have one daughter who
is a radiologist and another who is a dentist. Let us be honest: women have
a level of understanding that is higher than men's, not to point that out.
I have been a member of the board of directors of the American College of
Radiology for the past two years, and they have asked me to sit as an
observer. I have seen what has happened with the legislation there. The
problem is the way women interpret the information they receive. Let us be
honest, there is a forensic issue as well. I have been a radiologist for 33
years. I can spend half an hour doing an ultrasound on a woman, and I can
miss something. We know that 4 per cent of our radiology reports are not
what they should be.
Having said that, I believe that there really is a problem with the
organization of care. We are at the stage with this situation that we were
at 15 years ago when we started screening. I find that it is very important
that, as representatives of a national government, if you are going to use
this bill effectively to promote and do phase II screening, I am totally
open to it as a radiologist. I do this screening on a daily basis.
However, I have difficulty seeing myself in the current situation where
attending physicians would be inundated with calls. I can tell you what is
happening in Massachusetts and other states. In the United States, you can
ask for an ultrasound or not. Ultrasound training for American radiologists
is different than the training in Canada. For the most part, Canadian
radiologists are able to verify the work of technologists. That is a second
level that does not currently exist in the United States.
Yes, it is very good to be able to direct it in the context of a second
screening, but honestly, we do not have the resources we need to do 15
additional screening ultrasounds. We will quite simply not be able to do it.
I think the right information needs to be given. There must also be
coordination with the various jurisdictions through the federation or
Senator Verner: I would have one last question about the bill.
The Chair: I thank the witnesses on behalf of the committee.
We are very pleased to welcome two more witnesses to our discussion. Dr.
Boyd, please proceed.
Dr. Norman Boyd, Senior Scientist, Campbell Family Institute for
Breast Cancer Research, as an individual: I circulated in advance a
summary sheet. I apologize if it covers material already familiar to you. It
will not take me long to go through it and establish some basic facts that
appear to be in dispute from the earlier discussions that I heard.
Density is illustrated in the figure at the top right-hand corner of the
sheet. You can see there are mammograms with varying amounts of white in
them. The white is referred to as breast density. You can see that it may
occupy the entire breast, as in panel F, or it may be completely absent, as
in panel A, or it may be present in intermediate amounts in the remaining
These variations in the appearance of the mammogram reflect variations in
the underlying tissue composition of the breast: The breast lobules that
make milk under appropriate circumstances; the ducts that conduct the milk
to the nipple; and the connective tissue that supports those tissues looks
white, while fat tissue looks black. Variations in these tissues cause the
variation in the appearance of the breast.
Why does density matter? I think there are three reasons. The first is
the one you spent most of the last hour discussing: It makes breast cancer
more difficult to detect. The difficulty increases with increasing amounts
of density in the breast; therefore, breast cancer is most difficult to
detect in panel F and easiest to detect in panel A.
The second is that breast density is associated with an increased risk of
breast cancer. When someone says that something increases the risk of breast
cancer, the next question, I would suggest, is: Compared to whom? If we
compare someone with the appearance in panel F to the appearance in panel A,
we see that the gradient in risk is something like four-fold or five-fold,
which is much stronger than any other risk factor except for age and the few
genes known to create a very large increase in risk.
The difference across the spectrum of density is very strong. One can
also compare people with above average density, let us say those in panels E
and F, with women of the same age, for the same length of time in the
population and find the increase is about two-fold. The "Compared to
whom?" question has a profound influence on the quantity that one assigns
The third reason for being interested in this subject is that density, in
contrast to almost all other major risk factors for disease, can be changed.
We know little about how to change it at the moment, but we know that some
women who take combined hormone therapy — estrogen and progesterone
components — may experience an increase in density. Women who take
tamoxifen, a drug used to prevent breast cancer, may experience a reduction
in density. It can be changed by some things. There are also more general
influences, such as having children, aging, menopause, and so on, that also
decrease density. It is not an immutable thing. Whether these changes are
associated with changes in risk is much less certain. Some exposures, like
tamoxifen and hormone therapy, appear to be associated with both changes in
density and changes in the risk.
In terms of what can be done to decrease the risk if a woman is told that
she has increased density, if she is on hormone therapy and her density has
increased, she might discuss with her doctor whether it is advisable to
stop. Similarly, if she is very concerned about risk, and perhaps there are
other risk factors in addition to density, it might be appropriate to
consider taking tamoxifen as a preventive treatment.
One of the puzzles about density is it that it becomes less as women get
older, whereas we know the incidence of breast cancer increases. Data not
yet published shows that if we consider cumulative exposure to density, not
just the level of density but its duration, and integrate the area under the
curve created by plotting those things, we find a function that increases
with time and is very closely related to the age-specific incidence of
breast cancer in the Canadian population.
Current research on density is focused in a variety of areas. One is the
development of methods to predict breast cancer risk using density and all
the other risk factors that we know about and automated methods in the form
of the Gail model. They are all available on line for anybody to access and
use. There is research on development of methods to measure density,
particularly automated methods, and Dr. Yaffe is involved in that
We know that density is a highly heritable characteristic. One of our New
England papers that I included was a twin study with about 1,000 pairs of
twins collected in North America and Australia. In both populations, it
shows very strong evidence that inherited genes influence the type of
density that women develop. Research to try to identify those genes is in
We are also engaged in research on the origins of density in adolescence.
We are looking for factors in growth and development both before birth and
after birth. We find convincing evidence that they affect the way in which
breast tissue develops in adolescence. Development in adolescence determines
essentially what will happen throughout the rest of the woman's life.
The Chair: I now invite Martin Yaffe to present.
Martin Yaffe, Senior Scientist, Sunnybrook Research Institute, as an
individual: Good morning, and thank you for inviting me to testify at
this Senate committee considering Bill C-314 on the issue of communicating
information regarding breast density. You have heard much about breast
density before, so I will tell you about my background. My value here may be
mainly in answering questions you may have.
My background is in medical imaging physics. My research has been devoted
to the development of new techniques that can more accurately detect breast
cancer. My group at the University of Toronto helped to lead the development
of digital mammography, which is now the major technique used for breast
cancer screening. The first funding for this research came from the former
medical research council of Canada now known as the Canadian Institutes for
We designed digital mammography precisely to attempt to overcome the
problem of finding breast cancer in the dense breast. In a study carried out
in the U.S. and Canada in which over 50,000 women participated and were
imaged with both technologies, we were able to publish our findings in the
New England Journal of Medicine that showed that digital mammography
was substantially more accurate than film in those women who had dense
I was co-author of a study led by Dr. Anna Chiarelli from Cancer Care
Ontario and published a couple of weeks ago. It showed that one type of
digital technology was less effective than other types in detecting breast
cancer. I have collaborated with Dr. Boyd for many years on measurement
techniques for breast density. The technique that we developed together is
used in many epidemiological studies by other researchers internationally.
My current work is focused on optimization and evaluation of digital
breast tomosynthesis, which is a type of three- dimensional mammography that
may resolve some of the problems, but not all, around density and both
improve sensitivity of breast cancer detection and reduce the number of
false positives associated with breast cancer detection.
I should disclose that I am a founder and shareholder in a company called
Matakina Technology, a company that develops software to measure breast
density. In light of this, you may be surprised by my comments regarding the
You have heard from Ms. Kimberly Emslie, Dr. Morag Park and others about
the fact that breast cancer is a major killer of women. You have also heard
that high breast density imposes two different types of risk. First, women
with dense breasts are more likely to develop breast cancer than women of
the same age with less dense breasts. Second, mammography and even digital
mammography is less accurate in detecting breast cancer in the dense breast
and in determining that breast cancer is not present where it is present.
The false positive rate is higher in the dense breast.
Bill C-314 is well intentioned in expressing the value of communicating
to both a woman and her health care provider that she has dense breasts.
Certainly this information, as you have heard from Dr. Boyd and others, is
potentially valuable. With reference to the first type of risk, it is
important to know that there are many other risk factors for breast cancer
besides density. Related to this type of risk, we are only getting part of
the story in the discussion of density, so the discussion needs to be more
complete. I see density as one tool that would inform a more extensive
discussion between a woman and her primary health care provider regarding
the issue of risk.
The second type of risk, missing cancers in dense mammograms, could be
more directly addressed by providing a woman and her health care provider
with information regarding her breast density. I strongly believe that both
should be informed if it is deemed that there is a reasonable probability
that a breast cancer will be missed because of obscuring density. This could
trigger a recommendation for the use of additional or alternative screening
modalities that would be less negatively affected by the presence of
density. Some of these have been evaluated for specific indications but not
generally necessarily for general screening or for dense breasts. Therefore,
further research is necessary. In spite of that, there is reason to believe
that these techniques will provide more useful images in women with dense
breasts. Examples are ultrasound, digital breast tomosynthesis and breast
The goal could be achieved more reasonably with the adoption of
appropriate clinical practice guidelines requiring clear communication of
concerns regarding density, rather than through legislation. Until we have
further evidence on the efficacy of these new imaging tools, like MRI and
ultrasound for general screening purposes, I suggest that the person best
qualified to determine whether the presence of density is likely to
interfere with accurate interpretation of a mammogram is the radiologist.
This is the person who could most competently advise on whether ultrasound
or MRI should be used in a specific situation in addition to or in this
place of mammography for an individual woman.
There are, however, important areas in which the Government of Canada
could beneficially influence the practices of breast cancer detection
through screening. For example, the policies across the provinces on
standards for screening are not consistent, particularly with respect to the
age at which women are allowed access to organized provincial or territorial
screening programs. The Canadian government could, through the CBCSI,
influence a move to harmonize these policies across the country.
The recent recommendations of the Canadian task force, which based its
analysis on data that were not reflective of the performance of modern
breast screening technologies, did not provide a clear picture of the
benefits of screening, nor on the severity of the toll of breast cancer on
For example, 14 per cent of the deaths due to breast cancer and 18 per
cent of the years of life lost to the disease come from breast cancers
diagnosed when women are in their forties, a period during which the task
force has recommended against routine screening.
My research suggests that approximately 200 lives could be saved in
Canada each year if women in their forties participated in breast cancer
screening, but the task force recommendations have actually discouraged
these women. As you have heard from Dr. Wilson a couple of days ago, not
only women in their forties but many over the age of 50 have been
discouraged from participating in screening because of the message from the
task force. Screening is like fire insurance. Most people do not benefit
from it but those who do benefit do in a major way; not just through
aversion of a premature death, which is very important, but also through
earlier detection and allowing a woman to avoid possibly some of the harsher
aspects associated with treatment of advanced disease.
Here are four other opportunities that could help us to achieve maximum
impact against breast cancer and are amenable to action by the Government of
There are still important unanswered questions surrounding some of the
issues of which I speak. The government can ensure that federal funding
agencies have the resources to provide adequate research funding toward the
causes of breast cancer, its possible prevention and improved methods for
detecting those cancers that have the potential to be lethal since not all
breast cancers will necessarily become lethal.
It also would be of value to implement standards to ensure that all of
those who interpret screening mammograms have appropriate experience and
training, and therefore see enough breast cancers per year to be truly
competent at this. You have heard some remarks about that before.
Additionally, it would be of value that the government exerts its
influence such that screening is moved towards being done through organized
programs rather than opportunistically. Organized programs offer routine
invitations to women at the proper intervals for screening, quality
monitoring standards and measurement of outcomes associated with screening.
The Chair: I remind senators that by agreement of the committee
this session will end no later than 12:30. Since I had to cut off Senator
Verner in the last session, I have placed her third on the list and I will
begin in the regular way with Senator Seidman, followed by Senator Eggleton,
to be followed by Senator Verner.
Senator Seidman: Both of you have made it very clear that density
is a fairly complex issue and, as a single risk factor, likely not the best
way to inform women about their risk status. One would have to look at a
whole variety of risk factors in combination with density. We have heard
this from you and we have heard this from other witnesses.
I would like to ask you very specifically about actually assessing
density. We have heard from other witnesses that to have any objective
measurement of density is difficult. There seems to be not only a reader
bias or lack of reliability but there is also no absolute measure, or
agreement on an absolute measure, on how to measure density. Could you
comment on this please?
Mr. Yaffe: I mentioned the two types of risk for the risk
associated with higher risk of having cancer. An objective measurement and a
precise one is of great importance and perhaps Dr. Boyd will speak more
For the second one, to determine whether a mammogram because of density
may not be as useful as it might otherwise be, a much simpler criterion can
be used. You saw the images Dr. Boyd showed you and it is easy to see the
difference between a very dense breast and a less dense breast. Frankly, I
would trust the radiologist to be able to make the simple decision that one
image is of concern because of density and for another image a mammogram is
enough for now. This could be implemented with some training and very simple
Dr. Boyd: The estimates of risk shown in our 2007 New England
paper were generated by radiologists. They estimated the proportion of the
breast that was occupied by density using a kind of scale that is
illustrated in my figure. In Toronto, two radiologists, Dr. Roberta Jong and
Dr. Eve Fishell, sat down with each other and agreed on what they were going
to call density. We did a study of the calibration and ensured they could be
substituted for each other. Then they read the 2,000 or so images that were
assembled for the purpose of risk estimation and reproduced risk estimation
between the Canadian National Breast Screening Study, the population-based
screening program in British Columbia, and The Ontario Breast Screening
Radiologists can do this with their eyes. There is no need for complex
measurements. We did complex measurements in association with what the
radiologists did and we reproduced what they could already do. It is not as
difficult as one imagines. It may be that short education sessions would
improve reliability of measurement, but it does not need four years of
residency in radiology.
Senator Eggleton: Mr. Yaffe, in terms of your statement about
women in their forties, you point out that the task force recommended
against routine screening, but you are saying 14 per cent of the deaths due
to breast cancer and 18 per cent of years of life lost come from women
diagnosed in their forties. You then even say that approximately 200 lives
could be saved in Canada each year if women in their forties participated in
breast cancer screening. What argument did the task force make for not doing
it, because yours sound very compelling, and what do you say about the task
Mr. Yaffe: I believe you actually heard from others on previous
days when similar comments were made. I think the task force underestimated
the toll associated with breast cancer in women in their forties, and I do
not know why they did that. They certainly did not look at the years of life
Of course, if a woman dies at age 53 because of a breast cancer that was
originally found in her forties, there is a much greater loss of years for
that individual and that is a cumulative toll in society, than when someone
who dies at age 85 or 90 from a breast cancer. That was not considered, but
even in terms of death it is still quite a significant component of the loss
of life in the country. They ignored that.
They also did not look at more modern studies, using more modern
mammography in conjunction with modern treatment of breast cancer, including
some of the new therapies that we have available to us. For example, in
British Columbia, a study of their screening program showed a 24 per cent
reduction in mortality, which applied to both the younger women in their
forties and to older women. Studies that have been done in other countries
have even suggested larger benefits extending up into 40 per cent mortality
reduction. I believe they underestimated the benefit.
They also put a huge weight on what they call a false positive, and that
is not a mistake by the radiologist. A false positive indicates that there
is enough suspicion after the initial screening to suggest that a second
level of test be done to ensure that cancer is not present. This has been
painted as being a huge harm, and if it is not communicated well to women
there is stress associated with being recalled after a screening. I think a
better communication job could be done to reduce that stress. They put a
huge weight on the negativity associated with the so-called false positive,
and I believe this tended to colour their thinking on the matter.
Senator Eggleton: Let me ask both of you about the technology. The
Ontario government recently put $25 million on the table to replace
mammography screening equipment that uses the more traditional form of
mammography. I take it that it is to go to digital mammography. Is that the
right move? There so many changes in technology. Of course, the Americans
are now getting into the ultrasound in terms of dense breasts, over and
above the traditional mammography.
Is that the right move?
Mr. Yaffe: This is a fairly complicated question. First of all,
their move was not to replace film with digital but to identify one type of
digital mammography referred to as CR. In their evaluation — and I was an
author on the paper — it did not perform as well as the other type of
digital mammography or film, to basically remove that type of technology
from the program.
The subtlety is that there are multiple manufacturers of that CR
technology. The study was not powered statistically in order to sort out the
performance among the different manufacturers, so the government decided to
simply replace that generic type of technology with the DR type of digital
mammography. There are other factors in the measurements I do as a physicist
that suggest that move technically makes sense. The performance should
improve, I think.
Senator Verner: Mr. Yaffe, you mentioned that there was an
organizational problem with respect to resources. This is something that we
have heard from other witnesses as well, in other words, not necessarily
telling a woman that she has dense breast tissue, but knowing what happens
afterwards. That is where the problem lies, and it is particularly complex
when it comes to the organization. Could you please expand on that a little?
Mr. Yaffe: I am not sure that I said exactly that, but certainly I
think, and you have heard from others, that how to communicate the issue is
critical. You do not want to create panic. At the same time, if a woman has
been examined using a mammography — let us say a site is still using film
technology which we know does not perform as well on dense breasts as some
of the newer digital systems do — and the radiologist finds the breast is
dense and has concerns about the fact a cancer might be present and not seen
because of density, I think it is appropriate for a woman and her health
care provider to know that so that another examination can be done. It may
be just going to a digital system or adding MRI or ultrasound; it is not for
me to judge. However, I think the woman should be given that information so
she is part of the decision and I do not think it is grounds for panicking.
It is simply saying there is better technology we can use in this particular
case to get a clearer picture. I think it is the radiologist who can help
influence that decision as to who needs the additional views.
Senator Verner: Is there enough training to detect and treat an
issue like dense breast tissue?
Mr. Yaffe: Again, I may have a little built of difficulty with the
question, but I think that if it is a matter of recognizing high breast
density, as Dr. Boyd mentioned, relatively simple illustrations of the dense
breast and non- dense breast, most radiologists who look at mammograms know
which ones are problematic. Their job is finding cancer in mammograms. It is
a bit like if you are flying in an airplane in the clear blue sky and you
see an Air Canada plane painted white. You can see it. If you are flying in
a cloudy sky, it is more difficult to see. Radiologists quickly know which
ones are more problematic, can segregate them and identify the ones where
other imaging is perhaps needed.
Senator Verner: How would you describe our practices in Canada in
this respect compared to what is done elsewhere n other countries, for
Mr. Yaffe: Practices in what sense?
Senator Verner: In the sense that there are figures that were
mentioned earlier about the target number of radiographs that radiologists
do, meaning about 500 to 1,000 mammograms, compared to Sweden, where the
number is much higher, and the United Kingdom, as well.
Mr. Yaffe: I understand. I think the situation has improved in
Canada, somewhat. Previously, radiologists were required to read only 480
mammograms a year. At a typical rate of five cancers per 1,000, that means
someone might see only two or three screening cancers per year. In my
opinion — and I would defer to the radiologists here in the room — that may
be challenging to keep up one's skills seeing so few screening cancers.
In England it is 5,000 or 10,000, and that provides a better situation.
In the United States it is still 480 and part of it is the availability of
radiologists, particularly in smaller communities. If you demand this high
volume, you may find some communities do not have somebody to interpret the
images. Unless you do more centralized interpretation, which is what Dr.
Duchesne suggested, you might be in a situation where you do not have the
services available in the community. It is a balance. I do agree that the
evidence seems to be that higher volume improves performance both in finding
cancers and identifying the non-cancers and not having to call as many women
Senator Verner: Since we are talking about resources that are
perhaps not as well-organized, that there should be additional training and
that everyone is working in good faith on this issue, would you say that
with Bill C-314 we are looking at the problem backwards and should instead
look at the resources overall that could be improved before getting to that
point? Perhaps the federal government's regular agencies like Health Canada
or other initiatives could provide information on dense breast tissue,
rather than have this legislation address only this subject.
Mr. Yaffe: I agree and thank you for asking that question. I am
glad you asked it. That is why I mentioned that I am not sure a bill is
really the best way of addressing this issue. In some places they already
report density. If we knew that clinical practice guidelines would be put in
place to ensure this was done — and that it is done in a relatively
consistent manner — that would address most of the problem. I did mention
three or four other issues that I think are more pressing and would have
greater impact in terms of saving lives associated with breast cancer
Dr. Boyd: The debate about density raises a larger question. There
is great heterogeneity in the population with respect to both underlying
breast cancer risk, which is influenced by density and other risk factors,
and the ease with which cancer can be detected by mammography. To have
screening programs in which there is one modality and one screening
frequency for everyone, regardless of this heterogeneity, makes no sense to
me at all. There is a need to look at the things in a bigger picture and say
there are some women in whom the risk is lower and detection is really easy.
Do we need to see those people with the same frequency that we do those in
whom risk is high and detection difficult?
The Chair: Thank you both for those important answers.
Mr. Yaffe: I agree with Dr. Boyd on that issue. Not with respect
to density as a factor but with respect to other risk factors, in Ontario, a
high risk screening program has been implemented by Cancer Care Ontario.
Women who have greater than 25 per cent lifetime risk of breast cancer are
given the opportunity of being screened with MRI, mammography and/or
The Chair: Thank you very much.
Senator Seth: As I said, this has been an interesting topic.
Dr. Boyd, as you mentioned, breast density can be decreased by stopping
hormone replacement therapy or starting tamoxifen treatment. Can you explain
what these treatments are typically used for and their side effects?
Dr. Boyd: Hormone therapy is usually given to control symptoms
occurring in women at menopause. There is now convincing evidence from
randomized trials done in the United States that combined hormone therapy,
which is what is most commonly used, is associated with a modest increased
risk of breast cancer, which has greatly decreased the use of that drug.
However, in some women, it increases density, and there is evidence, not
yet published — the paper on which Dr. Yaffe and I are both co-authors from
a study done in the States — showing that the increase in density that
sometimes occurs with combined hormone therapy is very closely linked to the
increased risk of breast cancer. In women whose density changes on hormone
therapy, it should be regarded as a red flag and the question should be
raised as to whether they should continue. That is obviously a clinical
decision. It depends upon how long the doctor is planning to continue the
hormone therapy and how severe the symptoms are that are being treated, so I
think it has to be individualized.
Conversely, with tamoxifen, apart from its use in treating breast cancer,
its only real use at the moment is in breast cancer prevention, and it is
typically given in circumstances where the risk is very high, often with a
family history. However, it has recently been shown that in some women
tamoxifen decreases density substantially, and the decrease in density seems
to be very closely linked to the decrease in breast cancer risk that
accompanies use of the drug. This is still, I think, in a sort of
intermediate stage; it is not yet ready for clinical practice but it may
well become so in the near future.
The U.K. is beginning a randomized trial of women with extensive density
who are either put on tamoxifen or not, so we will shortly know what the
benefits are. Tamoxifen is not risk free. It can increase risk of clots,
pulmonary emboli, strokes and so on. The frequency of these things is very
low, but there has to be a substantial benefit in order for these risks to
be worth running at all. It is still a little muddy, but it illustrates the
principle that density can be changed, and changing it seems to be
beneficial in terms of the effect that has on breast cancer risk.
Senator Martin: I have learned from being a part of this committee
and serving in the Senate that nothing is simple. This bill is concise, but
it is a complex issue. Thank you for the work you are doing on shedding
light on this very complex issue.
Dr. Yaffe, in your presentation you mentioned the importance of raising
awareness and informing women as well was doctors. You wonder whether it
could not be achieved simply through adoption of appropriate clinical
I think we have learned so much in our committees, and we understand
where the gaps are and how difficult it is to close those gaps. You
mentioned harmonizing policies with provinces and territories. Could you
comment more on the complexity of adopting these clinical practices and/or
harmonizing? In the previous session, a witness said this bill — whether it
is this bill, an amended bill or another bill — would be the opportunity to
begin the process of doing some of those important things to close those
gaps. Would you comment on the complexity of trying to harmonize? What
challenges are we facing right now?
Mr. Yaffe: With respect to implementation of clinical practice
guidelines, I am not a physician myself. It is not clear to me in some cases
how simple or difficult this would be to do. I know that in Ontario around
the issue of MRI for women at high risk of breast cancer, clinical practice
guidelines were established quickly and efficiently over a period of several
months using data available in the literature.
I think if there is a will, there is a way to do this, and it should not
be that complicated. Many screening programs and many radiologists already
report density using the so-called BI-RADS lexicon which is in four
categories, and I think the category of greatest concern is the extremely
dense one. That is the one where the radiologist will have most difficulty
in finding cancers, so I think that it would not take a huge effort, if this
was the goal, to achieve some consistency across the country, and using
simple tools, illustrations, for example, to try to clarify those
If you are trying to measure density for the purposes of a trial to see
if a drug is influencing density or not, then the tools you need are much
more precise. Dr. Boyd and I spent a lot of time working on those things. I
do not think that is really what we are talking about here.
We will have such precise tools and they will probably be available in
the near future. I mentioned the company I am involved with, and that is
what we are doing. There are other people looking at that as well. That may
make things easier for the physicians so they do not have to make the
decision themselves, but I do think they can make that decision. I agree
with Dr. Boyd there.
I am not sure if you wanted to go beyond density, but I think there are,
as I mentioned, many opportunities to improve the situation around breast
cancer detection in the country. I think these are ones where better
consistency among the provinces is required and perhaps another look at the
task force and what it has done and to look at whether those are considered
acceptable recommendations and, if not, perhaps to consider revising them.
The federal government has been rather silent on the issue of its
Senator Martin: It is encouraging to hear you say that, and I will
specifically connect the work that you do, which is the research. I share
the concerns of my colleagues and what we have heard about the capacity in
our current infrastructure. If we are to inform, then how would we address
the next step of following up on caring for the women with dense breast
Based on the scientific research, the technologies and the expertise in
Canada, do we have the ability to build that capacity if the will is there
to bring the stakeholders together to do such good work?
Mr. Yaffe: I believe we do. The difference between the situation
we have here and in the United States, where much of the density publicity
came from in the legislation, is the way health care is paid for in this
country. In the United States, if something is not basically recommended
officially, a woman will have to pay for it out of her own pocket. In many
cases, that money just does not exist, so important things do not get done.
Here, I believe that in most cases if a physician feels an additional
test is valuable, he or she will refer a woman for that test, and it will be
done. If my doctor says that I need to go for this additional test, I will
take that advice generally.
With respect to having that discussion among professionals in the
country, there is certainly more than enough capability among our colleagues
to resolve those issues.
Dr. Boyd: The discussion you heard earlier this morning
illustrated very nicely that at the moment there is not a strong evidence
base on which to make decisions about what further imaging modalities might
be used. If the evidence is not available, perhaps we should get it. We
definitely have the resources within Canada to compare imaging modalities in
a systematic, quantitative way that would provide us with the evidence
needed to make these difficult decisions.
Senator Cordy: This has been very interesting.
We are dealing with the subject matter of the bill, which deals
specifically with the risk factor of breast density. Mr. Yaffe, one of your
recommendations, which you called an opportunity, which I like better, was
that federal funding agencies have resources to further research the causes
of breast cancer. What information gaps do we currently have related to risk
factors for breast cancer that would require substantial research?
Mr. Yaffe: As Dr. Boyd just pointed out, the question is if a
woman has dense breast tissue, what would be the best thing to do next? We
can make an intelligent guess right now, but the actual evidence in the
strictest sense has not been put together. I agree with Dr. Boyd that it
could be done in the Canadian environment and it would not be that difficult
to do if we just decided to ask the question.
One important thing is that automated breast ultrasound screening is not
generally available, but some of the other tools are. Some of these things
could be evaluated in what we call the post-market environment; in other
words, it is already out there and we could be doing studies to amass the
evidence to answer some of these questions, and we could do that without
Senator Cordy: So really this bill is jumping ahead. We do not
really know what we should be doing because we do not have the research
information to know the next steps for a person who has dense breast tissue.
Mr. Yaffe: Yes. For example, a study on ultrasound screening for
women whose only indication is a dense breast has not been done. It has been
done for high risk women. The same is true for MRI. Those studies, in the
proper context of how you would want to use the information, should be
Senator Cordy: The research end of that is certainly within the
realm of federal government jurisdiction.
You also spoke about implementing standards to ensure that those who
interpret screening mammograms have adequate training. Are there currently
no national standards?
Mr. Yaffe: The Canadian Association of Radiologists has now
imposed the standard. They have raised the standard from the American one of
480 examinations per year to 1,000, I believe it is. They are generally the
organization that sets that standard.
Senator Cordy: It would not be the government setting the
standard; it would be the organization itself?
Mr. Yaffe: Some provincial programs may have their own standard.
My guess is that it is consistent with the CAR.
Senator Enverga: We have two great scientists here. Have you ever
done research on the breast density of males? We have been talking about
females. I know a couple of males who died from breast cancer and I am
wondering if there is anything ongoing in that regard.
Dr. Boyd: I have been asked that question before and I usually
reply that women are giving me enough trouble at the moment. I will only
deal with males after it is all solved.
The question is quite reasonable. Breast cancer in males usually arises
in the setting of gynecomastia, in other words, in the setting of some
breast development that occurred in the individual. It is quite plausible
that there is imaging information in the male that may be pertinent to risk,
but it has never been explored.
Mr. Yaffe: Breast cancer is about 1 per cent as common in men as
in women, but little has been done with respect to considering the density
Senator Enverga: You mentioned that there is a lot of research in
progress. How far are we from making progress on this?
Dr. Boyd: Next week I am presenting the first results from our
study of young women. We are recruiting 15- to 18- year-olds from the
Toronto school system. We have ethics approval and cooperation with the
Toronto District School Board, the Catholic School Board and some regional
school boards outside the city limits. We currently have 700 young women
enrolled. They are being examined with magnetic resonance because we do not
want to expose them to radiation. Magnetic resonance can be used to
characterize breast tissue in the same way that mammography can.
We are accompanying those breast measurements with detailed histories
from their mothers about what happened during pregnancy and in the child's
early life, as well as genetic and hormonal measurements that we are making
in the children themselves.
This is the first study of its kind on this scale anywhere in the world.
Next week we will be reporting on the effects of some very early influences,
like whether the mother gained weight during pregnancy, what the birth
weight of the child was and whether she was breast fed as an infant. These
all have an effect on the breast tissue characteristics that we measure when
they are 15.
These are very early influences, and they raise the question of something
that has been called developmental plasticity. In other words, variations in
the environment at critical stages of development can cause the development
of particular tissues to proceed along certain lines permanently. This is
already established in heart disease, and it looks very much as though it
will apply in the breast disease and breast cancer setting as well.
Senator Enverga: I am looking forward to receiving that kind of
Senator Eggleton: Bill C-314 is technically not here; it is
technically in the Senate. We referred the subject matter of this bill to
the committee. This will be our last hearing on this issue, following which
we will have to determine what we are going to recommend on Bill C-314.
We have varying reviews of this from a number of people. Some say it
might be helpful in some respects, some say it might be harmful, and some
say that it does not go far enough. One person I asked the question of said
that most of this is being done but the bill adds some emphasis and maybe a
higher federal role.
There is minimal information in this bill, which is not a government bill
but a private member's bill. Is it helpful or harmful? Does it add
sufficient emphasis to make it worth proceeding with or is it not worth
Dr. Boyd: It seems to me that if a woman wants to know what
information is in her mammogram that may affect the detection of breast
cancer or her future risk of breast cancer, there is absolutely no case for
denying her that information. Whether everyone should be told, whether they
want to know or not, is another matter. There are other settings, genetic
testing, for example, where people can say that they do not wish to know the
results. I would at least want to consider that possibility in the context
of interpreting mammograms and reporting what they say.
If a woman wants to know whether she has breast density or not, I think
she has a perfect right to know. This information is somewhat different from
most other medical information about risk. If your doctor wants to know
whether your cholesterol or blood pressure are posing any hazard to your
health, he actually has to do something; he has to take a blood sample and
get it measured or perform a blood pressure measurement. Here the
radiologist cannot help but see the risk factor. It is impossible not to see
it. The question is, should it be a secret known only to him or her, or
should it be transmitted to the subject it concerns, if they wish to have
it? I think the answer to that is really straightforward.
Mr. Yaffe: I agree completely. The real issue is whether this
needs to be done through legislation. If I was absolutely assured that the
CAR would make this part of their standards and that the CBCSI would
similarly impose this as part of a screening program — and I heard Greg
Doyle speak a couple of days ago here and he was certainly not in favour of
this — then I would not see the need for the bill.
I do not know what the options are.
The Chair: I wish to formally thank you, on behalf of the
committee, for being here, for the thoroughness of your responses and for
the great expertise that you represent.