Q: I’m confused by the contradictory messages around breast cancer screening. Should I be pushing for regular mammograms? Asking for genetic screening? Still doing a self-exam in the shower?
In medical science we are always learning and updating our understanding as evidence evolves, and there is plenty of controversy in the area of breast health. So it’s not surprising that many women are confused about who should be screened, how we should screen and even whether we should be screening for breast cancer at all.
If you think about the tests available to us now, genetic screening is the furthest upstream option available. This can be done through a simple blood test or sometimes a swab of the inner cheek, to determine whether a woman carries one of the two genetic changes that we know contribute to genetic breast cancer (BRCA 1 and 2). While this test doesn’t actually tell a woman if she will develop breast cancer, it does identify those who are at very high risk for the disease (and other cancers) because of their genetics. Many of these women will have a strong family history of breast and ovarian cancer.
Some of the controversy around this testing focuses on the implications of learning the results. For instance, if you decide to get screened, the results will have implications for your daughter’s level of risk. Same with your siblings, or other relatives. But what if they don’t want to know? In addition, it isn’t always clear what someone should to do with the information once they have it. Women may choose earlier or more frequent mammograms or breast MRI, or they may choose major surgery to reduce or eliminate their risk.
High risk screening programs like the Ontario Breast Screening Program are also available to women with a family history of breast cancer and they offer genetic screening in addition to annual imaging tests. While we can’t change our genes – women who choose genetic screening need to be supported in understanding their options before they start down that road.
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The low-tech breast self-exam is another thing women often ask about. When I was growing up, I was taught that if you want to take care of your health you should be examining your breasts in the shower every month. But according to all the big population based studies, self-exams don’t impact mortality rates from the disease. In other words, you are no less likely to die from breast cancer if you examine your own breasts, than if you don’t.
For some women, this is a relief. A lot of women in my practice have told me, “I examine myself because I know I’m supposed to, but I don’t really know what I’m looking for and it causes me stress and I’m constantly thinking I’ve found something.” To those women I like to say, good news! I hereby liberate you from having to examine your own breasts. (There’s even some debate and conflicting research now about whether regular annual examinations by a trained health care provider saves lives).
But for other women, the breast self-examination is an important act of empowerment, and gives them a feeling of engagement in their own care. The population-level data doesn’t always give you a sense of what’s right for you individually. However, any persistent change in your breast (a lump, thickening, nipple discharge, dimpling) should be reported to your health care provider as sometimes this is how cancer presents. If you notice these things, do a quick check on your other breast to compare and make sure that this isn’t how your breasts ordinarily look and feel.
The last kind of screening is mammography. We take it as received wisdom that, at 50, we should be having a mammogram every two to three years. Our current screening programs across the country offer screening to women who feel perfectly well, have no breast symptoms, and do not have a family history of breast cancer.
But underneath that veneer of medical consensus lies some controversy. The basic question is: does mammography provide a significant reduction in deaths from breast cancer? And what are the associated risks?
A Cochrane review showed that if we screen 2,000 women over 10 years, we would save one life. But, because of the high rate of false positives, 10 healthy women would become cancer patients and receive unnecessary treatment. An additional 200 women would experience a false positive, be called back and told they need more investigations and tests, only to discover that they don’t have cancer.
Now, these numbers are based in part on old trials. Newer technology that is being used now for mammography is much better, and if we were to repeat these large-scale studies using the most up-to-date technology, we might get different results. But you can see how this gets confusing!
I still recommend, currently, that women in my practice have mammograms starting at 50 – sooner if there’s a family history in a first-degree relative — because the medical guidelines haven’t changed. All the provincial cancer care agencies recommend screening mammography, as does the Canadian Task Force on Preventative Health Care. But the science is tricky. Ultimately the decision about breast cancer screening is an individual one, and women have to make the decision based not only on that science, but their own personal preferences and values.