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News

Breast density disclosure may do more harm than good

Laura Eggertson
CMAJ January 13, 2020 192 (2) E48-E49; DOI: https://doi.org/10.1503/cmaj.1095839
Laura Eggertson
Wolfville, N.S.
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  • RE: Breast density disclosure may do more harm than good
    Elizabeth Ewart
    Posted on: 13 January 2020
  • RE: Breast density disclosure may do more harm than good
    Martin J. Yaffe
    Posted on: 13 January 2020
  • RE: Breast density disclosure may do more harm than good
    Paula B Gordon
    Posted on: 13 January 2020
  • Posted on: (13 January 2020)
    RE: Breast density disclosure may do more harm than good
    • Elizabeth Ewart, Family Physician, Royal Inland Hospital Kamloops BC

    January 13, 2020

    To the CMAJ Editor,

    I read the recent article on Breast density disclosure with disbelief and concern. I am a family doctor in BC and in 2015, when 43yrs old, I was diagnosed with breast cancer after palpating a large lump in my left breast. My only risk factors for breast cancer were being female and having dense breasts. However, I did not know my breasts were dense at the time of my diagnosis because this information was never shared with me. If I had known that my breasts were extremely dense, I would not have allowed a normal mammogram to reassure my physician and delay my breast cancer diagnosis by three months.

    Women have the right to know their breast density. They have a right to know their breast cancer risks and how sensitive a mammogram is for them. They have the right to make informed decisions about breast cancer screening and their own health. To reason that disclosing ones breast density should be avoided to prevent unnecessary anxiety is unethical and paternalistic.

    I was involved in the establishment of a breast health clinic in our community in 2017. We see over 300 patients monthly at the clinic. All patients are informed of their breast density and given information on what it means. Not one patient has ever told me that knowing her breast density has made her more anxious. Instead, we are routinely thanked for taking the time to share and explain this information. Every patient seen at the cl...

    Show More

    January 13, 2020

    To the CMAJ Editor,

    I read the recent article on Breast density disclosure with disbelief and concern. I am a family doctor in BC and in 2015, when 43yrs old, I was diagnosed with breast cancer after palpating a large lump in my left breast. My only risk factors for breast cancer were being female and having dense breasts. However, I did not know my breasts were dense at the time of my diagnosis because this information was never shared with me. If I had known that my breasts were extremely dense, I would not have allowed a normal mammogram to reassure my physician and delay my breast cancer diagnosis by three months.

    Women have the right to know their breast density. They have a right to know their breast cancer risks and how sensitive a mammogram is for them. They have the right to make informed decisions about breast cancer screening and their own health. To reason that disclosing ones breast density should be avoided to prevent unnecessary anxiety is unethical and paternalistic.

    I was involved in the establishment of a breast health clinic in our community in 2017. We see over 300 patients monthly at the clinic. All patients are informed of their breast density and given information on what it means. Not one patient has ever told me that knowing her breast density has made her more anxious. Instead, we are routinely thanked for taking the time to share and explain this information. Every patient seen at the clinic is also informed on breast cancer risk reduction. This information is readily available on the BC cancer website (FIVE PLUS), Canadian Cancer society website and Dense Breast Canada website. It does not take much time to share this valuable information with women. Does it save lives? I’m not sure. Does it empower women to make informed decisions about their health? Most definitely!

    After my diagnosis I was very angry to know that my breast density was never discussed, disclosed or explained me. To think that I wasn’t given this information to save me from unnecessary anxiety is even more disturbing. As a primary care physician and patient who has had breast cancer, I implore health care providers to focusing on patient centered care and informed joint decision making when discussing breast density with their patients rather than the opinions of a policy based researcher and epidemiologist.

    Sincerely,

    Dr. Elizabeth Ewart MD FCFP

    Show Less
    Competing Interests: None declared.
  • Posted on: (13 January 2020)
    RE: Breast density disclosure may do more harm than good
    • Martin J. Yaffe, Cancer research scientist, Sunnybrook Research Institute, University of Toronto, Ontario Institute for Cancer Research

    Re: Breast density disclosure may do more harm than good by Laura Eggertson

    Ms. Eggertson, in her article got a few things right, but several things wrong. She correctly communicated the double-barreled risk associated with breast density. It is important for women and their healthcare providers to know when an individual is at increased risk of developing breast cancer. It is even more important that they be informed when there is increased likelihood of an already existing cancer being missed on a mammography screen because it is hidden by dense breast tissue. A woman with breast cancer who receives false reassurance of a negative examination is at risk of delayed, and in some cases, more harmful treatment once the cancer is found.

    My concerns about this article, begin with its title. Of course any activity can cause more harm than good if it is not done properly. But, why shouldn’t communication of breast density be done properly? And while the push to communicate information on density came from advocacy, there is plenty of solid and well reproduced quantitative peer-reviewed evidence to support the existence of those two risk factors.

    Ms Eggertson's article states that there are no definitive studies demonstrating that giving women information on their breast density will reduce breast cancer incidence. I don’t think that anybody has suggested that this would occur. Density is associated with breast cancer risk, but reducing density doesn’t...

    Show More

    Re: Breast density disclosure may do more harm than good by Laura Eggertson

    Ms. Eggertson, in her article got a few things right, but several things wrong. She correctly communicated the double-barreled risk associated with breast density. It is important for women and their healthcare providers to know when an individual is at increased risk of developing breast cancer. It is even more important that they be informed when there is increased likelihood of an already existing cancer being missed on a mammography screen because it is hidden by dense breast tissue. A woman with breast cancer who receives false reassurance of a negative examination is at risk of delayed, and in some cases, more harmful treatment once the cancer is found.

    My concerns about this article, begin with its title. Of course any activity can cause more harm than good if it is not done properly. But, why shouldn’t communication of breast density be done properly? And while the push to communicate information on density came from advocacy, there is plenty of solid and well reproduced quantitative peer-reviewed evidence to support the existence of those two risk factors.

    Ms Eggertson's article states that there are no definitive studies demonstrating that giving women information on their breast density will reduce breast cancer incidence. I don’t think that anybody has suggested that this would occur. Density is associated with breast cancer risk, but reducing density doesn’t necessarily reduce risk.
    The most actionable aspect of breast density is currently not its association with breast cancer risk but its use in deciding, for an individual woman, if a mammogram is or is not sufficiently accurate for her breast cancer screening. While there are quantitative computer methods for assessing density (disclosure – I developed such a program over 20 years ago), this decision can be made in a couple of seconds or less by eye by an experienced breast radiologist while looking at the mammogram. If the accuracy is likely to be compromised by density, then a woman should have the right to know this and consider alternatives.

    It is this lack of accuracy combined with the inertia of both government and the medical community in Canada to act on this information that led to a grass roots group taking on an advocacy role. They followed the example of women in the US who had the similar experience of having cancers missed due their having very dense breasts, not having been advised of this risk, and thus leaving them in the dark about the potential risks to their lives

    Will, as Dr. Sharon Batt, quoted in Ms. Eggertson’s article, asks, giving women with very dense breasts the opportunity to have supplemental screening save lives? Ms. Eggertson is correct when she points out that we don’t have direct randomized studies testing this, but these will probably never be conducted. Such studies are large and expensive and governments won’t fund them. But, despite the limitations of current screening that Dr. Batt mentions, many studies and overviews have clearly demonstrated that earlier detection reduces breast cancer deaths. Even the Canadian Task Force on Preventive Health Care acknowledges that early detection is life saving for women 40 and older, although they grossly underestimate the magnitude of benefit. That’s why we have had screening programs across Canada for almost 30 years. Therefore, it is logical that if screening doesn’t work as well and cancers are missed in very dense breasts there will be more deaths. If we can find those cancers more effectively in the 10-15% of women with the most dense breasts, and there is plenty of evidence that techniques like breast ultrasound and others can achieve this, we can avoid some of those deaths. Ms Eggertson's article neglected to mention that the FDA, considered by most to be an evidence-based organization, has now decided to make communication of breast density a requirement across the US.

    Ms Eggertson is correct that medical guidelines for managing dense breasts are vague and they should certainly be tightened up. The vagueness may arise because the threshold between acceptability and inadequacy of current screening will always be somewhat arbitrary and there are costs, workforce and accessibility issues around the provision of supplementary screening that must be addressed by providers.

    Ms Eggertson may have misinterpreted the quotation from Dr Tamimi, a highly reputable scientist. Dr Tamimi’s stated concerns are not about whether it is a good idea to communicate information on density, but that the messages have not been delivered as clearly and effectively as they should be.

    The answers to those concerns appear to be quite straightforward. First, drop the paternalistic attitude about “not worrying your little head”. Then, use national guideline resources to ensure that women are effectively informed when they have dense breasts and their mammograms are likely to be less reliable. Provide them with information on possible supplemental screening, so they can make their own decisions about screening. At the same time provide their physicians with accurate information on the strengths and weaknesses of those screening tools, so that they can discuss them knowledgably with their patients. Only then can the informed decision making process advocated by the Canadian Task Force on Preventive Health Care credibly take place. Finally, convey to women how they might reduce density-associated breast cancer risk based on lifestyle factors. While the evidence is less solid that such behaviour modification will be effective, losing weight and drinking less alcohol are unlikely to do any harm.

    All of this is doable today. Or we can accept the status quo and live with the consequences – more women dying of breast cancer unnecessarily.

    Martin J. Yaffe, PhD, C.M., Hon. D.Sc.
    Senior Scientist, Physical Sciences
    Tory Family Chair in Cancer Research
    Sunnybrook Research Institute
    Professor, Depts. Medical Biophysics and Medical Imaging
    University of Toronto

    Co-Director, Imaging Research Program
    Ontario Institute for Cancer Research
    2075 Bayview Avenue
    Rm S657
    Toronto, ON, Canada M4N 3M5
    Tel. 416 480-5715 martin.yaffe@sri.utoronto.ca

    Show Less
    Competing Interests: Martin Yaffe is a breast cancer researcher. His institution conducts collaborative research with GE Healthcare on topics related to breast cancer imaging. He receives no personal remuneration in that collaboration. Dr. Yaffe also is a shareholder in Volpara Health Technologies (NZ), a company whose products includes software for measuring breast density.
  • Posted on: (13 January 2020)
    RE: Breast density disclosure may do more harm than good
    • Paula B Gordon, Radiologist, Clinical Professor, University of British Columbia

    Editor,
    I was shocked to read Laura Eggertson’s article on Breast Density Disclosure in the latest CMAJ Newsletter, and concerned for the misinformation to Canada’s family doctors, which will ultimately harm their patients.

    Citing unnecessary anxiety as a reason to withhold important health information is patronizing. Dense breasts are associated with 2 important risks as outlined in the article: the risk that cancer will be masked on the mammogram and the increased risk of getting breast cancer. Mammograms miss over 50% of cancers in women with the densest breasts, so offering them only mammography for breast cancer screening is discriminatory1. Women with dense breasts deserve the same opportunity for early detection of breast cancer, as women with non-dense breasts.

    Large scale supplemental screening with ultrasound in Connecticut (the first state to mandate density notification) shows 3-4 cancers per thousand women screened2, and these ultrasound-detected cancers are almost all small, invasive and node negative3. NOT DCIS, which arguably may be “overdiagnosed.”

    If those cancers go undetected, they grow until they are detected by palpation, as “interval cancers,” which are larger at diagnosis and more often node-positive than screen-detected cancers. They tend to be higher nuclear grade, and more aggressive with a greater predominance of HER2 and triple negative molecular subtypes. They have a poorer prognosis compared to screen-detected canc...

    Show More

    Editor,
    I was shocked to read Laura Eggertson’s article on Breast Density Disclosure in the latest CMAJ Newsletter, and concerned for the misinformation to Canada’s family doctors, which will ultimately harm their patients.

    Citing unnecessary anxiety as a reason to withhold important health information is patronizing. Dense breasts are associated with 2 important risks as outlined in the article: the risk that cancer will be masked on the mammogram and the increased risk of getting breast cancer. Mammograms miss over 50% of cancers in women with the densest breasts, so offering them only mammography for breast cancer screening is discriminatory1. Women with dense breasts deserve the same opportunity for early detection of breast cancer, as women with non-dense breasts.

    Large scale supplemental screening with ultrasound in Connecticut (the first state to mandate density notification) shows 3-4 cancers per thousand women screened2, and these ultrasound-detected cancers are almost all small, invasive and node negative3. NOT DCIS, which arguably may be “overdiagnosed.”

    If those cancers go undetected, they grow until they are detected by palpation, as “interval cancers,” which are larger at diagnosis and more often node-positive than screen-detected cancers. They tend to be higher nuclear grade, and more aggressive with a greater predominance of HER2 and triple negative molecular subtypes. They have a poorer prognosis compared to screen-detected cancers.4-7

    Research from Italy showed that the highest Breast Density category, compared with the other three together, had double the invasive BC risk, 5X the risk of an interval cancer, and almost fourfold risk of advanced cancer.8

    The article quotes Professor Tamimi, who “worries that breast density results aren’t accompanied by clear messaging about how to reduce the risk of breast cancer, for example, by exercising, avoiding alcohol and maintaining a healthy weight.” However, the Dense Breasts Canada website gives this exact advice, 9 and the Canadian Cancer Society website discusses these risk factors, along with many others.10

    The article quotes Sharon Batt, who claims that the move to mandatory notification isn’t supported by evidence, because “We don’t yet know whether this focus on dense breasts will save lives.” This claim is based on the fact that there has not been a randomized controlled trial (RCT) of supplemental screening in women with breasts. There shouldn’t need to be one: we learned from the RCTs of screening mammography, that mortality reduction depends on the detection of cancers when they are small and not yet spread to the lymph nodes. So it shouldn’t matter whether they are found at the early stage by mammography, ultrasound, MRI, contrast-enhanced mammography or any other test. And we know from the research on screening ultrasound, that those are exactly the types of cancers found. These are called “surrogate endpoints.” In fact, a RCT of screening ultrasound is underway in Japan, and is already showing higher sensitivity, lower stage, and fewer cancers in the group receiving mammography plus ultrasound.11 And since reduced interval cancers are the prerequisite for reduced mortality, we will eventually have the proof. But women shouldn’t have to keep dying of advanced cancers, when we have adequate evidence already.

    Moreover, the article and recent guidance from the Canadian Task Force on Preventive Health12 did not consider the significant benefits of early detection aside from mortality reduction: The opportunity to have lumpectomy and avoid mastectomy; the opportunity to have sentinel node biopsy and avoid axillary node dissection and its complication of lifelong lymphedema, and the opportunity to avoid chemotherapy.13-16

    Ask the women whose early cancers were found on supplemental screening whether they would have preferred to avoid a false alarm, rather than have the opportunity for early detection. Women and physicians undertaking shared decision-making should use the information above, omitted in this news article. If they do, I doubt they would conclude that “Breast density disclosure may do more harm than good.”

    1. van der Waal D, Ripping TM, Verbeek AL, Broeders MJ. Int J Cancer 2017;140:41-4
    https://www.ncbi.nlm.nih.gov/pubmed/27632020
    2. Weigert J. Breast J 2017; 23:34-39
    https://www.ncbi.nlm.nih.gov/pubmed/27647744
    3. Berg WA, Zhang Z, Lehrer D, e al. JAMA 2012; 307:1394-1404
    https://www.ncbi.nlm.nih.gov/pubmed/22474203
    4. Boyd NF, Martin LJ, Yaffe MJ, Minkin S. Breast Cancer Res 2011; 13:223
    https://www.ncbi.nlm.nih.gov/pubmed/?term=boyd+NF+2011
    5. Pisano ED, Gatsonis C, Hendrick E, et al. NEJM 2005;
    353:1773–1783
    https://www.ncbi.nlm.nih.gov/pubmed/?term=pisano+ed+2005
    6. Boyd NF , Guo H, Martin LJ, et al. NEJM 2007; 356:227–236
    https://www.ncbi.nlm.nih.gov/pubmed/17229950
    7. Yaghjyan L, Colditz GA, Collins LC, et al. J Natl Cancer Inst. 2011; 103:1179–1189
    https://www.ncbi.nlm.nih.gov/pubmed/21795664
    8. Puliti D, Zappa M, Giorgi Rossi P, et al. Breast Cancer Research 2018; 20:95-102
    https://www.ncbi.nlm.nih.gov/pubmed/30092817
    9. https://densebreastscanada.ca/faq/
    10. https://www.cancer.ca/en/cancer-information/cancer-type/breast/risks/?re...
    11. Ohuchi N, Suzuki A, Sobue T, et al. Lancet 2016; 387:341-8
    https://www.ncbi.nlm.nih.gov/pubmed/26547101
    12. Klarenbach S, Sims-Jones N, Gabriela Lewin G, et al. CMAJ 2018; 190; E1441-E1451
    https://www.cmaj.ca/content/190/49/E1441/tab-figures-data
    13. Ahn S, Wooster M, Valente C, et al. Ann Surg Oncol 2018; 25:2979–2986
    https://www.ncbi.nlm.nih.gov/pubmed/29987612
    14. Coldman AJ, Phillips N, Speers C. Int J Cancer 2007; 120:2185-90.
    https://www.ncbi.nlm.nih.gov/pubmed/?term=coldman+aj+int+j+cancer+2007
    15. Shah C, Vicini FA. Int J Radiat Oncol Biol Phys. 2011; 81:907–914, 2011
    https://www.ncbi.nlm.nih.gov/pubmed/21945108
    16. Yaffe MJ, Jong RA, Pritchard KI. J Breast Imaging, 2019; 1:161–165.
    https://doi.org/10.1093/jbi/wbz038

    Show Less
    Competing Interests: Volunteer Advisor: Dense Breasts Canada and www.denebreast-info.org Stockholder, Volpara Solutions
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Breast density disclosure may do more harm than good
Laura Eggertson
CMAJ Jan 2020, 192 (2) E48-E49; DOI: 10.1503/cmaj.1095839

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Laura Eggertson
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