Proceedings of the Standing Senate Committee on
Social Affairs, Science and Technology
Issue 40 - Evidence - May 23, 2013
OTTAWA, Thursday, May 23, 2013
The Standing Senate Committee on Social Affairs, Science and Technology
met this day at 10:27 a.m. to examine Bill C-314, An Act respecting the
awareness of screening among women with dense breast tissue.
Senator Kelvin Kenneth Ogilvie (Chair) in the chair.
The Chair: Welcome to the Standing Committee on Social Affairs,
Science and Technology.
My name is Kelvin Ogilvie, a senator from Nova Scotia, chair of the
committee. I will invite my colleagues to introduce themselves, starting on
Senator Seidman: Judith Seidman from Montreal, Quebec.
Senator Eaton: Nicky Eaton, Toronto, Ontario.
Senator Enverga: Tobias Enverga from Ontario.
Senator Cordy: Jane Cordy from Nova Scotia.
Senator Dyck: Lillian Dyck, Saskatchewan.
Senator Eggleton: Art Eggleton, senator from Toronto and deputy
chair of this committee.
The Chair: Thank you, colleagues, and welcome, guests. I will
identify our witnesses individually as I invite them to make their
I remind everyone that we are studying the subject matter of Bill C-314,
An Act respecting the awareness of screening among women with dense breast
We have three very important witnesses with us today. By prior agreement,
we will start with Shelly Jamieson, Chief Executive Officer for the Canadian
Partnership Against Cancer.
Shelly Jamieson, Chief Executive Officer, Canadian Partnership Against
Cancer: Honourable senators, I would like to thank the committee for
inviting me to speak. Today I plan to discuss the partnership's mandate,
provide a brief overview of the partnership's unique model and discuss our
role with regard to breast cancer screening.
Since joining the Canadian Partnership Against Cancer as CEO last year, I
have been ever more struck by the impact cancer has on the lives of
Canadians. Raising awareness about risk for cancer and what that may mean
for individuals is an important aspect of how we can work together to reduce
the impact of cancer in the future. My fellow witnesses are examples of the
kinds of experts we work with to understand how evidence informs the best
approach to accomplish that.
The partnership was established by the Government of Canada in 2007 and
is funded by Health Canada. We are a pan-Canadian organization that is
mandated to implement the Canadian Strategy for Cancer Control, which is a
30- year vision for achieving key outcomes. It is noteworthy that Canada is
one of a handful of countries with a national cancer control plan.
The partnership supports the uptake of knowledge and evidence emerging
from cancer research and best practices. We do this through large-scale,
multi-jurisdictional and organizational efforts that drive toward the
important outcomes of, one, reducing the incidence of cancer; two, improving
the quality of life of those going through an experience of cancer; and
three, lessening the likelihood of Canadians dying from cancer. We work
across the continuum of cancer control, from prevention and screening,
through treatment, to survivorship and palliative and end-of-life care.
The partnership's unique contribution to the cancer landscape is rooted
in our collaborative approach, where all our activities are done jointly
with partners across the country, provincial and territorial governments and
cancer agencies, cancer researchers and clinicians, NGOs and patient groups,
and many other organizations. We ensure partners realize value for
participating in the work so that together we can make progress in cancer
control more quickly, more effectively and more efficiently across the
country than if we had worked alone.
One of the partnership's strategic priorities is to develop high-impact,
population-based cancer screening approaches. We do this through a network
model that engages experts and partners responsible for the delivery of
screening programs in the provinces and territories. A key role of the
networks is assessing and disseminating new evidence and emerging best
practices to drive improvements in screening programs and to increase
Canadians' participation in evidence-based screening, specifically across
four disease sites: colorectal cancer, cervical cancer, lung cancer and,
more recently, breast cancer.
For instance, we have recently brokered a dialogue regarding prostate
cancer screening and the use of low-dose CT scanning for smokers at high
risk of lung cancer. We do this by engaging partners and experts about what
the evidence tells us and by coming up with practical solutions with them
for acting on that evidence.
Because of the partnership's mandate and the strategic focus of several
components of the Canadian Breast Cancer Screening Initiative, it was
transferred from the Public Health Agency of Canada to the partnership just
last month. The partnership will work with the Canadian Breast Cancer
Screening Initiative to support its efforts to improve screening.
As new evidence becomes available, the partnership will work with and
through the network and other experts to assess that evidence and its
implications for screening to inform planning and practice. For example, we
need to better understand whether there is a link between increased
screening of women with high breast density and mortality from cancer. This
could provide an opportunity to investigate it further.
In addition, the database of the Canadian Breast Cancer Screening
Initiative provides longitudinal data that allows us to investigate gaps or
areas of emerging evidence, and to improve quality in breast cancer
screening. As another example, more information is needed about the
over-diagnosis that could result from an increase in screening frequency
among women with dense breasts.
Translating evidence into practice and communicating with Canadians in a
way that is supportive and drives positive behaviour change are other
aspects of the screening networks' work. Where there is a gap between
evidence and Canadians' behaviours, specific tactics to engage with the
public are delivered locally within jurisdictions and communities.
Our experience has been that when opportunities to develop joint tools
and approaches to outreach exist, a systematic and coordinated approach,
working through and with a variety of organizations and professionals to
raise awareness, can have really positive results. This was the case with
Colonversation, an awareness program out of the Colorectal Cancer Screening
Network that was developed through our work and leveraged by many
jurisdictions across the country.
We also know that each time there are changes in screening guidelines,
people pay close attention. We have a responsibility to always ensure
information is grounded in evidence, that it provides clear direction and
that it minimizes unnecessary anxiety by helping Canadians navigate through
sometimes conflicting perspectives.
My intention is to reassure the committee that we understand the burden
breast cancer places on women and that the partnership is working to ensure
there continues to be a coordinated approach to breast cancer screening in
Canada. The partnership and all its partners are committed to identifying
and addressing gaps in evidence and ensuring that new evidence is reviewed
and acted on in a timely and effective manner. This includes raising
awareness of risks for cancer and the role of screening to improve the lives
I would like to thank the committee for providing the Canadian
Partnership Against Cancer an opportunity to speak today.
The Chair: I will turn to Gregory Doyle, Chair of the National
Committee of the Canadian Breast Cancer Screening Initiative.
Gregory Doyle, Chair, National Committee, Canadian Breast Cancer
Screening Initiative: Honourable senators, on behalf of the Canadian
Breast Cancer Screening Initiative, I am pleased to speak on Bill C-314, the
Breast Density Awareness Bill.
Organized breast cancer screening began in Canada in 1988. In 2013,
screening programs exist in all provinces and two territories. The evidence
for breast cancer screening comes from eight randomized controlled trials.
These trials showed that if 70 per cent of the population is routinely
screened, mortality from breast cancer can be reduced by 25 to 30 per cent.
Since 1990, the mortality rate from breast cancer in Canada has fallen by
over 35 per cent. This decline can be attributed both to early detection and
to improved treatment.
In 1993, Health Canada established the Canadian Breast Cancer Screening
Initiative. It is a partnership of provincial screening programs,
non-governmental organizations and professional organizations. Its purpose
is to develop quality programs that deploy best practice and to monitor and
assess program performance. In 2012, the initiative was transferred to the
Canadian Partnership Against Cancer.
Measures of mammographic breast density are captured in the Canadian
Breast Cancer Screening Database. However, the assessment and categorization
of breast density are not standardized.
There are several factors that increase a woman's risk of developing
breast cancer. High mammographic breast density is one of them. Increasing
age is the most common risk factor.
The routine interval for breast cancer screening is two years. A few
screening programs provide annual screening for women with high mammographic
breast density and other significant risk factors.
Breast screening programs have concerns with Bill C-314, and in
particular legislative mandates concerning breast density. The provisions of
the bill are vague and indeterminate. The bill could be interpreted to infer
that breast screening programs should routinely inform women of their
mammographic breast density. Not all programs make determinations of
mammographic densities, and the measure of density is very subjective, not
consistently reproducible, and there is significant inter- and
intra-observer variability. In addition, high breast density can be a
transitory condition that often decreases with age.
The bill refers to heterogeneous or dense breasts. Limited data from the
Canadian Breast Cancer Screening Database suggest that 35 to 40 per cent of
women have heterogeneous dense or dense breasts. This begs the question:
Does the bill impose the obligation on screening programs to inform up to 40
per cent of women that they possibly have the condition of heterogeneously
dense or dense breasts?
The dual mandate of breast cancer screening programs is, one, to detect
breast cancer early, and therefore reduce the mortality from breast cancer;
and, two, to confirm the absence of disease.
In 1968, the World Health Organization established the principles of
screening. Breast screening programs satisfy these principles. We have no
evidence to believe that screening for the condition of heterogeneously
dense or dense breasts satisfies the WHO principles. We do know breast
density is a risk factor for breast cancer, as are other factors and
conditions. We also know that it makes the interpretation of the mammogram
more challenging and that digital mammography is more effective in detecting
cancer among women with high mammographic breast density.
In 2011, the Canadian Task Force on Preventive Health Care set guidelines
for breast screening. The task force recommends women age 50 to 74 undergo
routine screening with mammography every two to three years. For women aged
40 to 49, the task force recommends against routine screening. The task
force undertook a systematic review to assess the benefits and harms of
screening. As for benefits, the task force determined that screening reduces
the number of deaths from breast cancer with the greatest impact being in
women aged 50 to 74. As for harms, the task force considered the harms of
screening to include false positive test results, which could lead to
anxiety, unnecessary biopsies and lumpectomies.
Advocates for informing women of breast density claim that the primary
benefit is gaining a better understanding of the relative risk of breast
cancer and the awareness of supplemental imaging options. There is no
evidence that providing information on breast density will impact the
mortality from breast cancer. A recent study in the Journal of the
National Cancer Institute indicated that breast density does not
influence death among breast cancer patients. In other words, even though
women with high breast density have a higher relative risk of breast cancer,
they respond equally well or better to breast cancer treatment.
What of the harms of informing women of breast density? Women will be
informed of a risk factor, but we are unable to tell them how to reduce this
risk. This will increase anxiety. Indeed, many women will seek alternative
imaging techniques, which will result in higher false positive rates, lower
positive biopsy rates and more unnecessary surgeries. Furthermore, we have
no evidence that additional imaging or other interventions will make any
difference in terms of breast cancer mortality.
The Canadian Breast Cancer Screening Database has been working on
standardizing how breast density is recorded. The initiative is
collaborating with Dr. Norman Boyd on his mammogram breast density and
cancer outcomes project. Dr. Boyd is using the database to identify subjects
for his study, which is investigating the association between cumulative
breast density and breast cancer. Dr. Boyd theorizes that cumulative breast
density is the stronger and more meaningful measure of breast cancer risk.
It is also a more complex measure.
While breast density is an exciting research area, it is of limited value
in the clinical setting. Before screening programs undertake to communicate
this information to women, we need to know what causes a woman to have dense
breasts, why breast density decreases over time, what the nature is of dense
breast tissue, how cumulative best density affects cancer risk and how
breast density can be reliably measured.
Before we have the answers to these questions, it is premature to require
screening programs to systematically inform women of their breast density.
If and when we do have answers to these questions, we will know who needs
more frequent and intense screening and who may need chemo prevention. Thank
The Chair: Now I will turn to Dr. Christine Wilson, Medical
Director, Screening Mammography Program of British Columbia through the
British Columbia Cancer Agency.
Dr. Christine Wilson, Medical Director, Screening Mammography Program
of British Columbia, British Columbia Cancer Agency: I would also like
to thank the committee for this opportunity to speak on breast density. I
will begin by discussing the most commonly used description of breast
densities and use this opportunity to show you specifics that relate back to
some of the points that Mr. Doyle made in his introductory speech. I will
also briefly discuss the state of breast density legislation in the U.S.,
and follow this with a summary of the Canadian task force recommendations,
which you have just heard about. I will also relate this to the impact that
this has had on some of the breast screening programs in Canada.
To begin, I will talk to you about the BI-RADS classification system.
This is only for a portion; you should have notes. This is in the notes, and
then I will show you some examples of mammograms in a few moments.
The BI-RADS classification system stands for Breast Imaging Reporting and
Data System. This classification system was developed and standardized
mammographic reporting in the U.S. It began in conjunction with, and
parallel to, the MQSA or Mammography Quality Standards Act. This was an act
that came into law in the U.S. in 1992 and brought into effect the review of
outcome data from mammograms by making mandatory follow-up of positive
mammograms and correlation of these mammograms with biopsy results. Normally
in those days it was surgical biopsy results. Also, the MQSA made it
mandatory that the final assessment category of the BI-RADS classification
lexicon was in the report; basically this was a bottom line for the
referring physician. They could read the report and they knew what to do
with the woman from looking at that report. These final regulations went
into effect in 1999, so BI-RADS has been in place in the U.S. for a number
of years, and the MQSA has done a great job in improving the quality of
mammography in that country.
The inclusion of best density in the report was not mandatory but it was
encouraged. The idea was to give the referring physician an idea of the
likelihood of cancer being obscured in that mammogram by the density. It was
not given as any kind of indication of risk.
When we talk about the BI-RADS classification system, we talk about four
types of breasts. The first one is mostly fatty, and I will refer you now to
the images; the second is scattered fibroglandular densities; third is
heterogeneously dense; and fourth is extremely dense.
That is a great view, but the light obscures the images over here. Later
you can look at these images.
That is an example of a mostly fatty breast. You can see there is lots of
grey tissue there. That is the fat. The small amount of white is the
Number 2 is the scattered fibroglandular densities. There is more white
scattered amongst the grey, and that is the fibroglandular tissue. Number 3
is heterogeneously dense. You can see there is a lot more white and some
grey intermixed. However, this is getting to be a dense breast. Number 4 is
extremely dense breast tissue.
The take-home points here are that you can realize just by looking at
these images how much more difficult it would be to find a cancer in that
breast — and there is a cancer there — in comparison to that breast.
Also, you can see how different people would make interpretations
differently about these types of breasts, particularly between 2 and 3, and
3 and 4. There is a lot of variation. This is a subjective determination;
there is no program that determines this at this time, though those sorts of
things are being worked on.
I would also like to mention one of the technological advances that has
really helped in looking at dense breast tissue, and that is the development
of digital mammography. The DMIST study, which was released in 2005,
demonstrated that digital mammography performed significantly better in
younger women — women under 50; women in their forties having mammograms —
pre- or perimenopausal women, and women with heterogeneously or extremely
dense breasts. You can see there is lots of overlap in those three. This
demonstrated that there was a sensitivity of digital mammography to detect
cancer at 70 per cent compared to a 55 per cent sensitivity in film screen
mammography, and there was no loss of specificity.
Also, to give you some background, when a woman is having a digital
mammogram, she cannot tell she is having one from the way that it is
performed — it is performed exactly the same; the machines appear to be very
similar. One of the advantages is that radiation exposure is reduced with
digital mammography. It can be up to 50 per cent of, but the average is
probably more around a third less than film screen.
Image acquisition takes just a few seconds. There are no films to
process. The image goes directly to a radiologist's workstation. It makes
the examinations shorter in the terms of the woman not having to wait around
to see if the film turned out.
To move now to the state of affairs in the U.S., right now there are six
states that have mandatory breast density legislation in place: Connecticut,
Texas, Virginia, California, New York and Hawaii. Such legislation requires
that radiologists notify women with dense breasts on screening mammograms of
the limitations of mammography in identifying tumours in the breast.
However, only Connecticut law requires insurance companies to cover
additional ultrasound screening of the entire breast if the density is
BI-RADS 3 or 4. Believe me, there is lots of controversy in the radiology
community in America around this. In the other states, therefore, or if
another test, ultrasound or an MRI is suggested and the woman does not have
coverage, that very much limits her access.
We do not have the same sort of limitations in access here in terms of
coverage, however we do have limitations in accessibility of the technology.
I can speak directly from my experience in British Columbia that we do not
have a surfeit of ultrasound technologists; there can be a wait of up to six
weeks for a routine breast ultrasound. We would be making the queues longer
and would perhaps be delaying the diagnosis of breast cancer in those women
who have it.
There is also legislation pending in an additional 16 states in the U.S.,
and a bill has been presented to the House of Representatives. In Texas,
they have taken a different approach; their legislation promotes a dialogue
between women and their physicians to find the most effective clinical
There has been now enough time in Connecticut that they have had a chance
to look at their outcomes. The first year of screening with the additional
ultrasounds revealed 3.2 cancers per 1,000. There is a mistake in the
material; it should be not per 100 but per 1,000. An additional 3.2 cancers
per 1,000 women screened has been detected with the ultrasounds in addition
These results are very similar to other large ultrasound screening
studies that have been done. I will direct you to the ACRIN 6666 results. It
has been the largest randomized trial performed using ultrasounds in
addition to mammography. It was two arms: one, screening mammography only;
the other arm, screening mammography and ultrasound. In the screening
mammography plus ultrasound arm, there were four times as many false
positives as in the mammography arm alone. That means that one in ten women
had an unnecessary biopsy, whereas only one in forty women had a biopsy that
turned out to be benign in the mammography arm. We have evidence that shows
that there are more biopsies being performed in these women.
I will turn now to the Canadian scene. Just to refresh your memory on the
Canadian Task Force on Preventive Health Care recommendations on breast
screening released in November 2011 in the Canadian Medical Association
Journal, these recommendations apply to women of average risk from ages
40 to 74. They do not apply to high-risk women, that is, women who have had
a personal history of breast cancer, women who have a BRCA mutation-positive
demonstrated, or women who have had previous chest wall radiation. There are
also no recommendation for women 75 years or older as there is a lack of
data in that group.
For magnetic resonance imaging screening in the average-risk woman, the
task force recommended not routinely screening with MRI. That is not a
controversial recommendation; that is pretty standard.
However, for women aged 40 to 49 years, the Canadian task force
recommended not routinely screening with mammography. I have a quotation
directly from that article:
This recommendation places a relatively low value on a very small
absolute decrease in mortality and reflects concerns with false-positive
results, the incidence of unnecessary biopsies and overdiagnosis of
For mammography in women 50 to 69, the task force recommended routinely
screening with mammography every two to three years, and for women 70 to 74,
routinely screening with mammography every two to three years. In British
Columbia, since these guidelines came out, we have seen a decrease in
attendance at the screening mammography program of women in their forties —
but not only women in their forties but women in their fifties as well.
Also, the task force recommended not routinely performing clinical breast
examinations alone or in conjunction with mammography to screen for breast
cancer. They recommended not advising women to routinely practice breast
self-examination. That is highly controversial among my primary-care
physician colleagues. They have concerns about that. There are, of course,
randomized trials that show convincing evidence about these two areas, but
it is an area of concern. I will just highlight that.
I want to show you very briefly what the background is for the concern
from the task force about screening women in their forties. This next table
shows you the age groups on the left-hand side, the number of trials, and
they are listed on the next page. These are the randomized trials that Mr.
Doyle referred to. They are international trials and highly regarded — all
of them randomized.
They showed a definite benefit to women in the screened group in terms of
mortality in the three age groups of 39 to 49, 50 to 59, and 60 to 69. That
is what the third column refers to. You can see that, in those age groups,
the value is less than one: 0.85, 0.86 and 0.68. This indicates there is a
statistically significant decrease in mortality in those women.
The controversial area is the next column — the fourth column. You can
see that they determined the number needed to invite is over 1,900 women in
that group of women in their forties as opposed to 1,339 women for the
fifties. They felt it was exposing too many women who are normal to the
possibility of having additional investigations, including additional
mammograms, ultrasounds, biopsies and possibly surgery.
That was the reason for their statement.
In British Columbia, we have taken a bit of a different stance. We have
reviewed our guidelines. We have not released them yet; we will be shortly,
hopefully. We have added an additional group of women that we consider to be
higher-than-average risk. We are will allow them to attend the screening
mammography program annually. These are women with a first-degree relative
with breast cancer — a mother, sister, daughter, brother or father who has
had breast cancer. These women will be able to attend annually.
I will just give you again briefly some background on the screening
mammography program in British Columbia. This is the oldest screening
mammography program in the country. It began in 1988, so we are celebrating
25 years of operation this year. We have performed 1.4 million screening
mammograms, and we have detected breast cancer in over 16,000 women in that
At this time, we do screen women aged 40 to 49 annually and they can
self-refer. Women 50 to 79 are screened every two years; they can also
self-refer. They need to have a family doctor or nurse practitioner to
receive results, however, so that can be a bit of a problem for those women
who do not have a doctor.
Women are not eligible if they are symptomatic, if they have a past
history of breast cancer or if they have breast implants.
In 2011, the year for which we have the most complete statistics at this
time, we performed over 305,000 mammograms and detected 1,464 cancers. We do
perform standard two-view mammograms, as do all of the programs across
Canada. We have 38 fixed centres in urban settings and three mobile vans
that visit over 120 smaller B.C. communities, including First Nation
communities and some hard to reach communities such as Downtown Eastside
Vancouver. They also go to large utility corporations and that type of
setting. The mobile performs 10 per cent of the exams per year. Screening
mammography is funded by the Ministry of Health with its own separate budget
and is coordinated by the BC Cancer Agency Screening Mammography Program.
Screens are delivered, performed in health authority clinics in hospitals as
well as in community imaging clinics, which may be owned and operated by the
radiologists who work in the hospital across the street.
The cost to the system for a screening mammogram is $73. We screen over
300,000 women per year, and about 7 per cent of those women will require a
Diagnostic breast imagining refers to mammograms performed for women who
are symptomatic, but also those who have positive screens. They may include
additional mammographic views, ultrasounds, biopsies and other tests. They
are also performed for women referred by family doctors or other physicians.
However, this is a fee-for-service service funded by the Medical Services
Plan and also delivered by health authority and community imagining clinics.
The cost of a bilateral mammogram to the system is $131. There is a
considerable savings to the system by having asymptomatic women go through
This slide shows the volumes that we perform and how they have increased
with the population over the past number of years. The blue shading shows
the women attending for the first time.
The next slide shows the participation rates of women in breast screening
programs across the country. British Columbia has about 56 per cent
participation. The red line shows the national participation rate of about
46 per cent. This slide shows the regional participation rate in the
screening mammography program throughout the province. We do have regional
variation, a little lower in the northern part of the province, higher in
the urban centres such as Vancouver and Vancouver Island.
This is an interesting slide that shows the number of cancers detected in
the age groups from 2007 through 2010. You can see that they stay remarkably
stable. In women in their forties, the cancer detection rate is around 16
per cent. The number of cancers found in the age group is 16 per cent on
average. In the 50 to 59 group it is 30 per cent, 60 to 69 around 30 per
cent, and 70 to 79 is about 20 per cent. There is only 2 per cent in the
those aged 80 and above. It stays pretty consistent year to year, and 80 per
cent of the cancers detected by the screening mammography program are in
woman 50 and older.
I have one small note about outcomes because this is very important; this
is why we are doing this. You can see from this slide, which is taken from a
Lancet article of 2010, these countries keep large population cancer
registry databases. This shows the one-year and five-year survival rates of
women who have had breast cancer by percentage. The outcomes are very good
in Canada, but you can see that British Columbia has better outcomes than
the Canadian average and our outcomes are as good as the Swedish outcomes.
Thank you for your time; that concludes my presentation.
The Chair: Thank you. I will turn to my colleagues, beginning with
Senator Seidman: Thank you. That is an awful lot of information to
digest all at once, so I will start trying to pick a bit at the major issues
you put forward.
First, I will start with a bit of conversation about the Canadian Breast
Cancer Screening Initiative because, Mr. Doyle, the initiative is directly
implicated in this bill. I would like to start by asking you this: Did
anyone consult you or the initiative when this bill was discussed and
designed by the promoters?
Mr. Doyle: No, this is our first opportunity to talk about the
bill here today.
Senator Seidman: Even when this bill was discussed in the House of
Commons, no one had you there to discuss the implications for the
Mr. Doyle: No.
Senator Seidman: I am asking because the initiative is directed
with responsibility in this bill.
(c) sharing through the Canadian Breast Cancer Screening
Initiative information related to the identification of heterogeneous or
dense breast tissue during screening and any follow-up procedures.
That would be the requirement in the bill, would it?
Mr. Doyle: Yes, that is correct.
Senator Seidman: Is there a current sharing of information across
Mr. Doyle: With respect to mammographic breast density?
Senator Seidman: Yes.
Mr. Doyle: As I mentioned in my submission, currently breast
density is recorded by some provincial screening programs. It is not
consistently categorized in a systematic way across the country, and some
provincial screening programs do not record breast density. We do not do it
consistently and the method for recording is not consistent across the
country at this point in time.
Senator Seidman: You referred to that and went further, in fact.
The point that you make about breast density in your presentation is also
identified by the American College of Radiology in their comments on the
American legislation in the various states on breast density awareness. You
say that the measure of density is subjective, not consistently reproducible
and dependent on observer variation.
Mr. Doyle: That is very true. We know from screening programs in
the provinces that do collect breast density records that sometimes it
depends on which radiologist is interpreting the image. It could go from one
category to another. Currently in the country, some provincial screening
programs use the BI-RADS methodology that categorizes breast density in
quartiles. Other provinces use a method where it is recorded as greater than
75 or less than 75. It is a binary classification, which makes it easier,
and that reduces the variability because you can only be in one of two
categorizations. There is no real consistent methodology to capture that
Senator Seidman: The assessment of breast density is not reliably
reproducible in that sense?
Mr. Doyle: No.
Senator Seidman: That leads to the next point you made. We all
know that the screening programs can be good, but one always has to be sure
that the benefits outweigh the risks.
Mr. Doyle: When I spoke about the dual mandate of screening, we
try to find cancers early but we also attempt to confirm the absence of
disease. The idea of breast density is a condition that the bill is implying
that we should inform women about. We are not detecting disease and we are
not confirming the absence. We are telling women about a condition that may
be a risk factor, but we have nothing to offer them when we inform them of
Senator Seidman: That is the point, right?
Mr. Doyle: Yes.
Senator Seidman: If you have a screening program and are telling
women you have this condition, you need to be able to offer them something
to make that of any value?
Mr. Doyle: The purpose of a screening program is to either find
disease or confirm the absence of disease. This is the idea of screening as
set out by the World Health Organization. There is a set of principles, and
when you apply screening for heterogeneously dense or dense breasts to these
principles, it sort of fails. It does not satisfy the principles of
screening as set out by the WHO.
Senator Seidman: There is another concern here. You say that the
prevalence of dense breasts is close to 40 per cent.
Mr. Doyle: The terminology that is used in the bill is
heterogeneously dense or dense breasts. That is terminology that corresponds
to the BI-RADS system used in the United States that Dr. Wilson spoke of.
Heterogeneously dense is the categorization of greater than 50 and less than
75, and very dense or dense is greater than 75. We have limited data
because, as I said, all provinces do not collect it, but we can look at the
provinces that did collect in the quartile. Some collected greater than 50
or less than 50, but we come up with an estimate of somewhere approaching 40
per cent. The American College of Radiology says it is higher, and they
quote it as being closer to 50 per cent. That is the challenge, then,
because if as a screening program we inform women of this condition then
women are going to be looking for supplemental imagining and it defeats the
purpose of screening.
Senator Seidman: Are you suggesting that there needs to be, and I
think Dr. Wilson also addressed this, perhaps a more sensitive screen, that
you cannot just use one risk indicator such as dense breast tissue but you
might have to add to that things like a first-level relative with breast
cancer or age or something?
Mr. Doyle: The routine interval for screening is two years. The
task force recommends two to three years. A number of screening programs
bring a set of women back on an annual basis, and that is based on risk
factor, so it is based on family history. Density influences that in a
number of provinces. If a woman had radiation for leukemia or lymphoma to
her chest in her early years, that would influence it. That influences the
interval of screening. The routine interval is two years, but some sets of
women we screen more frequently.
Senator Seidman: My concern is the false positive and the points
that you make, and perhaps all three of you have referred to it, the concern
that this will create unusual anxiety in women, who then go off for many
other kinds of tests and are put through additional radiation exposure at
the minimal, or biopsies or surgeries. That is a concern, there is a no
question, especially if you are talking about upwards of 40 per cent to 50
per cent of women with this condition, as you described.
Mr. Doyle: The crux of the problem is that we do not have any test
that is reliable that we would apply on this large group of women to add any
value. We can only see that it is going to do more harm than good.
The Chair: Dr. Wilson, do you wish to comment?
Dr. Wilson: In British Columbia, we can reliably determine family
history, as that is something that women report every time they come for
screening, and we also have international data and also data from our own
program to show that women with a first-degree relative do have twice the
risk of developing breast cancer. We have elected to use that as our
determinant of annual recall. Most women are recalled every other year;
those women will be eligible to come back every year.
Senator Seidman: This is not for woman with dense breast tissue
Dr. Wilson: No, this is everyone. There really is not any evidence
that shows that women of average risk but with denser breasts should be
recalled at a greater rate than anyone else. That may be something that
comes out of some of the studies that are ongoing, but as it stands now, we
do not have that evidence.
Senator Seidman: I have one last thing, and maybe I can ask for
your conclusion on the subject matter and the potential legislation, which
could have serious consequences.
Mr. Doyle, you also mentioned in your presentation, and I am familiar
with the study, that the Journal of the National Cancer Institute
indicated that breast density does not influence breast cancer deaths
amongst breast cancer patients.
Mr. Doyle: This was a study done by a group called the Breast
Cancer Consortium in the United States. They are similar to the Canadian
Breast Cancer Screening Initiative. They do not cross all U.S. states, but
there is a consortium of states, and they have a database just as we have a
database. Because they have that act in the states about the BI- RADS and
the MQSA, they have always categorized density. They have categorical
information on a woman's breast density according to the mammogram, and then
they looked at outcomes of women who had low-density breasts versus women
with high-density breasts, of a set of women who had breast cancer, and they
found there was no difference.
Women who have dense breasts respond well to treatment. If you know
anything about breast cancer treatment or if you know any women who have had
breast cancer, you will hear them talk about triple-positive estrogen, ER PR
positive, and the negative. Woman who are positive are more inclined to have
the dense breasts and they respond much better to treatment. There is a
correlation between the type of cancer that you get with high mammographic
breast density versus the type of cancer you get with low density.
Senator Seidman: The women who have high-density breast tissue
respond equally well or better to treatment and therefore have no additional
risk of death compared to other women?
Mr. Doyle: Yes. That was a study that came out last August. It is
a very good study.
Senator Seidman: I appreciate that.
Based on everything I have heard from you, and everything you have added,
Dr. Wilson, in your experience in screening for breast cancer, have you had
an opportunity to look at this bill and do you have something to suggest in
terms of what we might add, subtract, whatever?
Dr. Wilson: First, the bill is to be lauded in that it does bring
attention to this. Anything that brings attention to the detection of breast
cancer is probably a good thing. I think going too far down the road with
the legislation is a problem, and it is a problem as I have outlined
particularly with access for additional testing, because again we do not
have the data to show how beneficial that additional testing will be. We
know there will be a large downside, which is access and additional
As the task force has already indicated, they feel that screening
mammography already may contribute to that. Particularly, in younger women,
that is a bit of a problem.
Certainly, the mandatory legislation that is in place in the U.S. would
not work here, in our setting.
Senator Seidman: Thank you. I appreciate that.
Senator Eggleton: Let me follow up on the bill itself, Bill C-314.
Mr. Doyle, in your presentation you said that you have concerns about the
bill, about legislative mandates concerning breast density. Provisions of
the bill are vague and indeterminate, you also said, and you go on from
there to explain that.
Picking up on what Senator Seidman was talking about, further on in your
written comments you state:
So what of the harms of informing women of their breast density?
Women will be informed of a risk factor, but we are unable to tell women
how to reduce this risk; this will increase anxiety.
Are you saying that this legislation could actually be harmful?
Mr. Doyle: If we apply the principles that the Canadian Task Force
on Preventive Health Care applied to evaluating the harms and benefits of
screening I would say yes, it would be harmful. That would be my assessment.
Senator Eggleton: I direct this question to all the witnesses. Do
you think there are amendments that could be made to this bill to remove
that harm, reduce that harm or make the bill more useful? Just a few moments
ago Dr. Wilson said it adds some emphasis to this thing and provides a
further focus so that might be good, but how can we amend this?
If you do not have an answer to that now, I would be happy if you sent us
some thoughts on specific amendments.
Mr. Doyle: My forte is not amending bills, but before we would go
to this area I mentioned five questions that we need answered. If the bill
wanted to achieve something it would look at trying to provide the necessary
infrastructure and research agents to answer those questions.
Within the initiative and working with CPAC, if the bill is as it is, we
would obviously work with it and try to standardize how breast density is
measured. We are very doubtful that we are going to have any impact on
mortality, and from a public health consideration that is what screening
programs are about. They are impacting mortality rates writ large.
The Chair: Before I go to Ms. Jamieson, I will ask you this
question: The medical profession has a model of ``do no harm.'' In its
current form, is the answer to that question yes or no?
You have been very careful in the breadth of your answers.
Mr. Doyle: I thought about being questioned on the bill and giving
a one-word response; I would say the bill is unnecessary.
Dr. Wilson: I have to agree.
The Chair: I will leave it there and go to Ms. Jamieson for her
comment and her answer to my question as well.
Senator Eggleton: I would like an answer to my question as well.
The Chair: I apologize, senator. Yes, would you respond to Senator
Eggleton's question and then to the question I put?
Ms. Jamieson: I will try to do both at once and say, as Dr. Wilson
said, whenever we raise awareness about specific issues to do with cancer we
are doing a service to the people of Canada. We need more people talking
about and more people aware of risk factors, lifestyle choices and screening
obligations as a person. We need all of that and we do it in a lot of ways.
We can do that through policy or procedure, or a guideline or the way the
system is structured. We could do it through media campaigns and we have
done that. We need anything that raises awareness. In that tool kit,
legislation is one of the options. It would be helpful if a piece of
legislation came along and spoke to the issue of screening and said that
more research needed to be done to understand the role of breast density. I
think we would all applaud that.
The way I would say our partnership is set up is that we listen to
experts who help us understand what is truly evident so we are not winging
around with whatever can happen and unnecessarily scaring people. I would
say that the screening initiative would love to sit down and talk about what
is next in this regard. As with other kinds of cancer, at CPAC we help
people across the country in cancer control collect information in the same
way and understand best practice.
This morning I have heard people say there is not enough information
across the country, we do not collect it in the same way and we are not sure
if there is evidence that leads to one path or another. Those are all good
things to investigate; we are just not there yet.
Senator Seth: I would be very interested to know if we are
concerned about dense breast tissue in women, or heterogeneous breasts. Is
it a problem? Have you done any major study that proves that cancer is more
common in dense breast tissue? You have said there is no evidence that
providing information on dense breast tissue will impact mortality from
When I look at the picture here of dense breast tissue it looks white.
When a patient goes for screening, and for mammography, a tiny cancer looks
white and dense breast tissue looks white as well. It will hide. When it
shows that, what are we supposed to tell the patient? Do you say that you
have a very heavy, dense breast and it could be a cancer there, maybe, but
you are not sure? Should we not have some provision for follow-up?
Now you are saying if dense breast tissue is detected there will be a
follow-up, more mammography, more biopsies will be performed and there will
be more false positive results. Do you not think that with 1 in 10 false
positive determinations, in terms of life, if you follow those other 9
patients they may have a cancer hiding underneath that white patch, which
looks white anyway? Cancer looks white and dense breast tissue looks white.
Would we be saving a life, too?
What is the wrong with having awareness and being more careful, with more
follow-up by doing the mammography or automatic ultrasound, in order to be
able to save a life?
Dr. Wilson: You have completely outlined the controversy. To begin
with, this is the controversy we deal with in mammography screening and then
also extending this now into other testing.
With screening mammography, unlike other areas of testing, we have the
randomized control trials that show that there is a reduction in mortality
for the women who receive breast screening. We know that from the randomized
trials. Women who get breast screening do have a reduction in breast cancer
mortality. We do not have that evidence for those other tests.
I do the breast ultrasound; I am the province's breast expert in MR, and
I believe strongly in both of these as tools. However, we do not have the
evidence to show that for average-risk women. These women are still
considered to be average risk because we, again, do not have evidence that
would elevate them just on the basis of breast density to
We are talking about average-risk women, and we do not have evidence to
show that doing further testing will detect breast cancer sooner and enhance
their longevity. That is really the crux.
Of course, you are also getting to another very important point, and that
is the emotionality around breast cancer and breast cancer detection. It is
something that many people feel strongly about. I am not saying that is a
bad thing — I feel strongly about it — but it does interfere with people's
interpretation of the data and of what needs to be done. It does add a
flavour that we try to, by using the randomized control data, take that step
back and look at what we can defend, and certainly what we can defend in a
publicly funded health care system such as we have in Canada.
Senator Seth: I still think, to my knowledge — what I see — it is
a good thing to be careful. The patient should be counselled. Anxiety will
be there if you say, ``Oh, you have dense breast tissue.'' We are supposed
to tend to the patients when the report comes.
Not only that, because you can under diagnose breast cancer that is early
stage — we can do a lot better than just leaving, saying the mortality is
not high enough. I do not know. It does not —
Dr. Wilson: We are not saying that. As we have also said and
emphasized, women knowing about their breast density is a positive thing. It
is not a negative thing; it is a positive thing. Yes, there may be increased
anxiety, which in some cases may be unnecessary, but these women probably do
need to be a little more cautious. They should be attending the screening
program more regularly and should be having these discussions with their
doctor, particularly if they have a change in family history, which can
We are saying, and I think the Canadian task force also emphasized this,
these are the sorts of conversations women need to have on an individual
level with their own family physicians. They have to understand what the
limitations of the technology are, and they have to be comfortable with
their choice in that they do not just blankly do whatever you tell them or
they do not refuse to do things. They need to have some sort of
understanding of where they lie, where their risks are, and they try to deal
with that appropriately for them.
The Chair: Let us allow Mr. Doyle to intervene.
Mr. Doyle: We should always recognize that we are talking about
population screening, so we are talking about large numbers of people. When
we think about screening, there are 40 per cent of women who would have
heterogeneous or dense breasts. It is just inconceivable then that we would
offer that set of women supplemental imaging like ultrasound, and I know
that many of the advocates of this type of breast density legislation are
all about advocating for ultrasound.
However, we know that ultrasound is very good for diagnostic purposes, so
we have to understand the difference between screening and diagnostic
examinations. We screen women who are well; all the women who come to
screening programs are well. Out of the thousand women who come, 995 or 994
of them do not have breast cancer. However, we are talking about 400 out of
that thousand having dense breasts.
Presently, out of that thousand women, 940 or 930 of them we tell them to
go home, not worry about it and come back in a year or two. However, with
this type of legislation, we would have to tell 400 of those thousand women
to have supplemental imaging — go get an ultrasound. This would still be
screening, because we would not have a mammogram report that indicated an
abnormality — an area that an ultrasound would want to focus and do imaging
on. They would have to do general imaging on the breast, looking for a
needle in a haystack, not knowing where they were looking. Therefore, we
would have 400 of these women having ultrasounds, and they would have no
more information, by and large, because those cancers do not exist.
Out of the thousand women, there are six cancers. The screening program
finds five of them and there is one of them out there that we do not find.
We do not even know if it is among those 400 who would have an ultrasound;
it might be in the 600 who are not having any supplemental imaging. It is
the proverbial needle in the haystack. We would do these ultrasounds, the
radiologist would be looking at the ultrasound and saying, ``I do not even
know what I am supposed to be looking for.''
Ms. Jamieson: I will add one thing to that. The impact of that on
the system might be that people who really needed to be screened cannot get
in and are waiting longer and detection is delayed. It has a cumulative
effect in the system, as well.
Dr. Wilson: It is where there are long waits at times for
diagnostic ultrasound, in particular.
The Chair: You made that point in your presentation, Dr. Wilson,
very clearly — namely, that there could be a significant negative impact on
women as a whole with regard to this particular issue.
Do you have a different question?
Senator Seth: Still, I would say prevention is a lot better than
cure, and that is the whole idea of having this bill.
The Chair: Senator, could you move on to another question?
Senator Seth: Another question is —
Mr. Doyle: I would like to respond to prevention. We do not
prevent breast cancers in breast screening; prevention is not in our tool
kit. We do not prevent cancer in breast screening. We detect it early, but
we do not prevent it.
Senator Seth: That is a key factor — detecting early stage. It
means saving lives and doing better treatment.
Go ahead, it is an argument.
My second question is about something you mentioned in your speech. You
said self-examination — you do not encourage it.
Dr. Wilson: I did not say that. I said the Canadian Task Force on
Preventative Health Care, in their November 2011 recommendations, said that
they do not recommend advising women to perform breast self-examination.
That is their guideline. It is controversial.
Senator Seth: Do you agree with that?
Dr. Wilson: Do I agree with that? Well —
The Chair: I think we are getting away from the topic here, so I
will direct you to your next question, if you have one.
Senator Seth: Thank you, but I think it was related to that.
The Chair: That is a separate issue, senator.
The issues that we have covered here this morning have been, I think,
exceptionally helpful to us in understanding this issue, and in
understanding the significance of different aspects of the discussion around
the issue. It would be extremely unfortunate for a parliament to pass
legislation that would be harmful to its citizens. If doctors have a model,
``do no harm,'' surely a government must at least meet that test.
Our issue here is to further consider the issue before us in terms of the
subject matter, and to reach conclusions and advise the Senate of Canada
with regard to the issue that is before us.
First, I really want to thank my colleagues for asking —
Senator Cordy: I agree with what you are saying, but I did not
expect it to end so quickly.
The Chair: There was no indication from you that you wanted to ask
Senator Cordy: You are absolutely right.
The Chair: I will pause in mid-flight and invite the late Senator
Cordy to ask her question.
Senator Cordy: I do not disagree with what you are saying, even
about my being late.
It is not disagreeing with any one thing. I am quite interested in the
participation in provincial breast cancer screening programs. Dr. Wilson, in
the table that you gave us, the Maritime provinces are quite high, which is
good. Newfoundland is low. I am assuming that is because of the controversy
they had a few years ago. Oh, it is not about that?
Dr. Wilson: I will let Mr. Doyle speak to that, as he is from
Mr. Doyle: It is actually unfortunate that table was the one given
you by Dr. Wilson. In Canada, women access mammography through two different
methods: One is through organized screening programs, and the other is just
through getting a requisition from their doctor and going to a diagnostic
mammography centre, where they do routine mammography, which is screening.
If we looked at data from the Canadian Community Health Survey, we would
find that pattern across the country is very even — approaching 70 per cent.
I saw that and I thought, ``Oh —''
Senator Cordy: Alberta is a 0.6 and I thought, ``Wow. Why?''
Dr. Wilson: It is for the same reason: They mostly go through the
private offices, what I refer to as the CIC, the community imaging clinics.
Also, only a very small percentage are done by their mobiles.
Mr. Doyle: So that —
The Chair: Let us examine that stream of thought here, and then
Dr. Wilson can clarify.
Mr. Doyle: We can provide an update to give you a better picture
of the utilization of routine mammography across the country, because that
only captures a portion. It is how provinces organize the delivery of
services, and we are capturing only a portion of that delivery. However,
when we look at it on a pan-Canadian basis through a couple of different
data sets, it is a very similar pattern and it is approaching 70 per cent
across the country.
Senator Cordy: That would be helpful because for Newfoundland, I
made the assumption — you should never make assumptions — and for Alberta I
wondered because I thought financially they would be in a much better
Mr. Doyle: There is another table we can provide you.
Senator Cordy: I am also interested in breast screening in the
North. One of you mentioned earlier that participation rates in urban areas
are much higher. What about the northern communities, the Yukon, Northwest
Dr. Wilson: They do have a screening program in the Yukon and
Northwest Territories. However, I think it is sporadic, is it not, in the
Mr. Doyle: They have an organized program in Yellowknife.
Senator Cordy: Does it travel around like a mobile unit?
Mr. Doyle: No.
Dr. Wilson: We do a lot of mobile. Ontario uses a lot of mobile,
and so does Alberta.
Senator Cordy: Thank you, chair.
Senator Dyck: Thank you for your presentations this morning. They
were very clear, helpful. Dr. Doyle, you made it clear that it might be
premature to pass this bill because there are more negatives than positives
with respect to what the bill will do, that it will likely increase false
positives, increase anxiety, increase unnecessary testing and treatment.
Later on it was brought up that it might even harm not only those people who
have dense breast tissue, but might also have a negative impact on those who
do not because the resources available would be utilized to a greater
When I was listening to what you said, Dr. Wilson, I noticed with the
breast screening guidelines now for women aged 40 to 49 it is no longer
recommended that they have routine screening. I am wondering if that is an
equivalent situation because in that case there are greater concerns about
false positives, unnecessary biopsies and over-diagnosis. Would you say that
is a similar situation?
Dr. Wilson: Yes, that is why I brought that point up. It is
because we are now placing 40 per cent to 60 per cent of women who are
screened in the same category of having additional testing, which may or may
not be necessary. We feel that largely it is not necessary or we do not have
the data to show how effective it is and in what percentage we need to have
this. That is the point.
The Chair: I will now appeal to my colleagues, and I am seeing no
hands going up. I will now conclude by again thanking you for the way in
which you have explained this very important issue, which obviously has a
considerable amount of emotion around it, in addition to, if I could be so
bold to say, the pure medical or clinical issue that is under discussion in
I think you have been exceedingly helpful to us. On behalf of my
colleagues, I want to thank you very much for that.