Mammograms for Older Women

First, let me be very clear that the debate about the value of mammograms for older women does not apply to those of us who have had breast cancer. We are told to continue with annual mammograms forever. This discussion is about women who do not have a personal breast cancer history and are not at high risk for developing the disease.

Generally speaking, the statistical benefits of screening aren’t seen for 10 years.

But what does “older” mean? I have had some trouble finding a clear answer to that one. The one clear recommendation that I could find comes from the U.S. Preventive Services Task Force. They suggest that women stop having annual mammograms at age 75 regardless of other circumstances. However, there are guidelines from other professional groups that suggest continuing annual mammograms for older women who have a likely life expectancy of at least five more years.

Why are we talking about this? We know that the incidence of breast cancer increases with age and that early-stage breast cancers can usually be treated more simply and effectively. The Oncotype GX test has made it possible for women with ER-positive breast cancers—which is the type that most older women develop—to know if chemotherapy would be useful in their care and whether their cancer is more or less aggressive. This would seem to argue for continued screening.

However, the other side is that some older women might have better lives if they never know of a lurking breast cancer because they are likely to die from something else long before the cancer would be dangerous. This perspective is always a tough one to understand for those of us who have had breast cancer. We appreciate that, once learning of the diagnosis, difficult decisions must be made fairly quickly and life changes.

An example: If a woman is contending with other serious medical problems and very likely has a short life expectancy, does it help her to have to consider breast surgery, probably radiation therapy, and some kind of systemic therapy that may negatively impact her overall health and mood? Those of us who believe in the high value of self-determination likely think she should always have accurate information and a choice. But…

Muddying the waters further, no one knows with precision and certainty which cancers found on a mammogram actually need treatment at all because they are so slow-growing and might even have the potential to disappear on their own. I know that last phrase is controversial, but there it is. There is no way to identify these lesions because they have vanished. A Norwegian study from 2008 actually found fewer invasive breast cancers among women screened every six years vs. those screened every two years. Their conclusion was that some cancers must have spontaneously disappeared.

Countering that study is a more recent one that considered more than 750,000 mammograms done between 2007 and 2017 for women of all ages. Among those screenings, cancer was found in almost 4,000 women who were 75 or older. The study’s author, Dr. Stamatia Destounis, reported that most of those cancers were invasive and of types that should be treated. Dr. Destounis commented, too, that many women are living longer in good health and can reasonably hope for productive years as they age.

So, what is the bottom line? There is no evidence that screening women 75 and older with annual mammograms reduces cancer mortality. Generally speaking, the statistical benefits of screening aren’t seen for 10 years. There is also the worry, noted above, about overdiagnosis: finding cancers that are not going to harm an older woman in her lifetime, but knowing of them could cause a lot of trouble.

To help with this quandary, Dr. Mara Schonberg (an internist at BIDMC) and her colleagues developed a decision aide that asks 10 questions about a woman’s general health and medical history. The hope is that completing this short questionnaire can help an older woman and her doctor make an informed decision about the wisdom of annual mammograms.