Mammography has served as the gold standard for breast cancer screening for Canadian women for at least three generations but the resurfacing of some very questionable Canadian data based on flawed methodology is generating considerable confusion amongst women. No less an authority than the World Health Organization has deemed this study “flawed” but every few years, an update of the data resurfaces like some malicious toadstool to be flaunted by some non-science members of the media. The result is both angst in the public and is used as an excuse by cash poor provincial health ministries for cutting back on recommended age and time frames for screening. The basic conclusion of the study cohort states that “mammography does not reduce breast cancer deaths and offers no survival advantage over physical breast examination for middle- aged women”. The study further reported “although X-rays detected more invasive cancers, the death rate was virtually the same as the death rate in women receiving only physical exams”.
The third dictum of the study stated “more than 20% of screening detected cancers were overdiagnosed and would NEVER have grown large enough to cause symptoms or death if they had not been found”. The original study commenced in 1980 and involved a total of 90,000 Canadian women divided in to two age groups 40-49 and 50-59 with one half of each group receiving physical breast assessments and one half then receiving mammography annually for five years. I have three concerns with the methodology of this study. The first is an ethics question. No ethical nurse or doctor doing the initial examination is going to randomly place any patient with a discovered breast mass in to the non-screening group. In fact, non-screening patients were ultimately found during independent follow up to have arranged their own mammography outside the study. Its also important to remember the original five years of the study began in 1980 when much of the mammography equipment was a decade older (or more) with testing being done in multiple centres with variable skill levels and techniques meaning non -standardized interpretation; based largely on the level of experience of the radiology staff of the individual location. What irks me most about the study is the crystal ball conclusion that some cancers would never have grown large enough to cause symptoms or death.
I’ve never professed the ability to predict the future. Do you? Every woman has the right to make her own informed choices. Before you do so, let me offer a few caveats. New equipment and new techniques combined with upgraded examination skills significantly reduce radiation exposure and false positive results. Even with a positive diagnosis. the dreaded total mastectomy is rarely the first or only option. Ultrasound and MRI and even needle aspiration/ biopsy have been added to the diagnostic repertoire. But the first step for every women should be a self examination every few months. The youngest patient I ever diagnosed with breast cancer was 34 so there is no rule book. Examine yourself standing to look for asymmetry in shape then examine yourself lying flat. Remember breast tissue is located from the neck to bottom of rib cage in the front and from midline on the sternum to the deepest portion of the armpit where the draining lymph nodes are located.
For women in their 40’s, an annual physical is important, especially where there is any abnormality found or there is a relevant family history, I would urge mammography. For women over age 50, I would recommend a similar self examination protocol perhaps more frequently, definitely an annual physical breast examination as part of a more total assessment. For those women with no relevant history and no significant findings on physical, a mammographic screening every two years should suffice. Do not be embarrassed to ask your examiners the age of their equipment. There’s lots of sophisticated equipment out there but many a hospital has been frustrated acquiring it from provincial health ministry minions manning the vault.
For women past the age of 60, physical breast exam and follow-up mammography annually is the safest path to follow. My last caveat is just plain common sense.The earlier you find a problem, the more likely available treatment will bring you to safe harbour. It will always be your personal decision to make based on your own beliefs.
By: Dr. David Carll