Breast cancer is the leading cause of death in Canadian women 40-55 years old. The incidence starts rising at age 30, and incidence rises with increasing age. Screening mammograms were proven to reduce deaths in women from ages 40-74 in randomized controlled trials done from the 1960s-1980s. Cancer is less common in younger premenopausal women, but cancer in younger women grows faster than in older women because of the presence of ovarian hormones. It’s especially important that these cancers be found early. Currently, four jurisdictions allow women to self-refer to their screening programs starting at age 40. In Ontario, women between the ages of 40-49 cannot access a screening mammogram unless they have a referral from their doctor. Many physicians are reluctant to provide the referral, stating that they are following recommendations from Canadian Task Force (CTF).

The CTF on Preventive Health Care is comprised of experts in methodology, and includes epidemiologists, nurses, a chiropractor, and a nephrologist. It excludes radiologists who diagnose breast cancers and surgeons and cancer specialists who treat affected patients. The 2018 CTF guideline advises against mammography for women aged 40-49. The guideline is largely based on the Canadian National Breast Screening Studies (CNBSS).

Of eight randomized trials of screening done globally, the CNBSS was the only one to not show reduced mortality in screened women ages 40-59. The trials have now been proven to be invalid because the randomization process was compromised. It also ignored a 2014 study of screening in Canada that showed 44 percent fewer deaths among women aged 40-49 who had screening mammograms, than women who did not.

Screening mammograms reduce deaths from breast cancer starting at age 40. By allowing early detection of breast cancer, they allow less aggressive treatment, which increases quality of life for women with cancer. When found early, cancer can treated with lumpectomy instead of mastectomy; lymph node staging can be done by a small biopsy rather than a complete dissection of the armpit (with a much lower risk of long-term complications and arm swelling), and many women can avoid chemotherapy and return sooner to productive lives in the community.

There is no biological or scientific reason to wait for screening mammograms at age 50:

• 17 percent of breast cancers are found in women in their 40s.

• Women in their 40s represent 27 percent of the life-years lost to breast cancer and have the most years of life to gain when screening is performed.

• Black and Asian women have a peak incidence of breast cancer in their 40s and are discriminated by the CTF guideline.

Regardless of improvements in breast cancer treatment, survival depends on the size of their tumor at diagnosis.

Using modelling, Dr. Martin Yaffe, a leading Canadian breast cancer expert, recipient of the Order of Canada, Senior Scientist of Physical Sciences, Sunnybrook Research institute, and Professor of Medical Biophysicist and Medical Imaging at the University of Toronto, found that in provinces that do not currently accept women in their 40s into provincial screening programs, there is potential to reduce breast cancer deaths by 1.8 per 1000 women each year if those women started screening at age 40. This is equivalent to a 10 percent overall reduction in breast cancer deaths, or 400 fewer women in their 40s dying every year in Canada.

Dr. Jean Seely, Professor of Radiology at University of Ottawa, Head of Breast Imaging at the Ottawa Hospital and President of the Canadian Society of Breast Imaging notes the harms of delayed diagnosis of breast cancer in women in their 40s are prevented by early detection and screening. In light of this updated research, Ontario should consider adopting the Nova Scotia, Prince Edward Island, Yukon, and British Columbia model, allowing women to self-refer to screening programs starting at age 40.

There are no breast cancer experts on the Task Force. They consulted experts, but ignored their input. At this point, over 130 breast cancer experts have strongly criticized the guidelines.

One sixth of breast cancer deaths and 24% of the years of life lost to breast cancer are in women diagnosed in their 40s. Even with statistics like these, the Task Force does not recommend screening for women in their 40s. As a result, 4,000 Canadian women will die over the next decade if this recommendation is followed.

These exams are an important measure women can take to increase early detection of breast cancer, especially in women with dense breasts.

About 10% of women are recalled for additional images and this may cause understandably anxiety. The Task Force considers this anxiety a harm and uses it to dissuade women from screening. The anxiety is not long lasting. Better safe than sorry.

The Task Force does not acknowledge the benefits of avoiding chemotherapy, avoiding mastectomy and avoiding lymphedema.

The Task Force relies on outdated and flawed studies. The obsolete studies estimate that women are 15-20% less likely to die if they have breast screening. Current studies show that women who have mammograms are actually 40-44% less likely to die of breast cancer than those who do not.

The risks of dense breasts have been known for 40 years. Dense breasts increase the risk of developing breast cancer and increase the risk that cancer will be masked on a mammogram. The guidelines ignore the benefits of supplemental screening for women with dense breasts.

Using the CNBSS guidelines women may make decisions that may ultimately lead to a late diagnosis, unnecessary suffering and a poorer prognosis.

Senior Scientist, PhD

MD, RCPSC Radiologist, Professor

MD, FACR Radiologist, Professor

MD, FRCPC Radiologist, Professor

MD, RCPC Radiologist, Associate Clinical Professor