Is mammography in danger?

Not all that long ago in Canada, the triad of early detection of breast cancer was breast self-examination (BSE), clinical breast exam, and mammography.  These three were the most widely used tools in the early detection of breast cancer.

However, in the late 1990 and early 2000s, breast self-examination came under attack, and even such organizations as the Canadian Breast Cancer Foundation modified their recommendations from promoting BSE to promoting breast awareness “because there is insufficient or inconclusive scientific evidence of an effective BSE technique, or an effective way for health care providers to teach it to women, or that BSE reduces breast cancer mortality.” [1]

Although clinical breast exams (CBE) should be part of a regular check-up, many health care practitioners have either not been taught the correct way to perform CBE or do not have the time to include one in a patient’s annual check-up. In addition, the Ontario Breast Screening Program, which used to offer a clinical breast exam as well as a mammogram for women aged 59-70, no longer performs CBEs.

And increasingly, mammography has been under attack.

The latest in a fairly long line of studies that criticizes screening mammography is the Canadian National Breast Cancer Screening Study, “Too Much Mammography,” published on February 11, 2014 in The British Medical Journal ( This Canadian study followed approximately 90,000 women who were assigned to either receive regular mammograms or have no mammograms between the years 1980 and 1985. Researchers followed the participants for about another 25 years.

“During the screening period, approximately 660 invasive breast cancers were diagnosed in women who received mammograms, and about 520 cases were diagnosed in those who did not receive the screening. Among the women diagnosed through mammograms, 180 died of breast cancer, and 171 died from the group who were diagnosed without mammography.

“According to the findings, mammograms contributed to the over-diagnosis of breast cancer — meaning the screening detected a cancer that was not an actual threat to the woman’s health, but she still underwent chemotherapy, surgery, or radiation.”[2]

In her statement on the Canadian National Breast Screening Study, National Breast Cancer Coalition president Fran Visco says that the study “confirms NBCC’s long-held position that an enormous amount of resources and attention have been spent on mammography, despite the lack of strong evidence that screening significantly reduces mortality from breast cancer. The Canadian study found that 22% of women whose cancers were detected by mammograms were overdiagnosed and subjected to unnecessary treatment.”[3]

What’s a woman (or man) to do now?

Over 24,000 Canadians were diagnosed with breast cancer in 2013 – 23,800 women and 200 men[4] – so doing nothing is not an option, and early diagnosis is still important.

Already there are suggestions that we should take another look at breast self-exams and clinical breast exams.[5] Apparently one unexpected but positive outcome of the Canadian National Breast Cancer Screening Study was that “women who did not receive regular mammograms were instead monitored with physical breast exams that proved effective. All of the participants were taught to examine their own breasts once a month, and specially trained nurses examined women who were in their 50s. This low-tech approach, the researchers found, appeared to be as good as or better than regular mammograms at locating the serious cancers that needed treatment.”[6]Researchers went on to say that they were reluctant to address this, since it had not been the purpose of the study.

Confusing? Yes. Important? Undoubtedly. Implications for screening for other cancers? Evidently so:  several recent studies have reported on and described overdiagnosis and overtreatment of not only breast but also prostate and thyroid cancers, and to a lesser degree renal and lung cancer.[7]

But when it comes right down to it, existing breast cancer screening methods are still breast self-examination, clinical breast examination and mammography.

And in fact, in a February 14, 2014 media release, Dr. Jacques Lévesque, President of the Canadian Association of Radiologists (CAR), the national association representing radiologists in Canada, stated that, “Women should continue to seek breast cancer screening using mammography, a form of x?ray of the breast.” The CAR went on to say that they are very concerned that women will feel there is no need to pursue breast cancer screening, when in fact, several other breast cancer screening reports indicate the opposite.

The CAR joined the American College of Radiology and the Society of Breast Imaging, who also have concerns that the report is “incredibly misleading analysis based on the deeply flawed and widely discredited Canadian National Breast Screening Study (CNBSS). The results of this BMJ study, and others resulting from the CNBSS trial, should not be used to create breast cancer screening policy as this would place a great many women at increased risk of dying unnecessarily from breast cancer.”[8]

The recently released CAR Practice Guidelines and Technical Standards for Breast Imaging and Intervention, as well as referral guidelines for medical imaging for physicians, encourage women to speak with their physician about the right time to begin mammography exams.

The Canadian Cancer Survivor Network will continue to address issues in cancer screening as they arise. We encourage patients, survivors and caregivers to share their thoughts and opinions about cancer screening by writing to


[1]Look and feel,

[2]Doctors critical of mammography study,, February 24, 2014

[3]National Breast Cancer Coalition Statement on The Canadian National Breast Screening Study,

[4]Canadian Cancer Statistics 2013,

[5] A fresh case for breast exams by Roni Caryn Rabin,  The New York Times,






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