The Mammography Controversy

Today a new recommendation about mammograms was published by the American Cancer Society (ACS).

http://www.nytimes.com/2015/10/21/health/breast-cancer-screening-guidelines.html?_r=0


We used to do yearly tests starting at age 40; but there was really no hard evidence about how often and when to start. The US Preventative Services Task Force (USPSTF) started recommending every other year beginning at age 50.

http://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/breast-cancer-screening

The basis for these decisions is mainly the cost-effectiveness of the procedure and the risks involved. The risks are very minimal; the adverse complications from a negative biopsy are minuscule. We do not know the rate of false positives, which can result in unnecessary mastectomies. Cost benefit analyses are relatively arbitrary, but generally if the cost of finding one case exceeds $250,000 it is considered not cost effective.

In an editorial in the Journal of the American Medical Association, they commented:

"Because the risk of breast cancer is low for women in their 40s and to some extent women in their 50s, the modest relative benefit of 15% translates to a very small absolute benefit (approximately 5 of 10 000 women in their 40s and 10 of 10 000 women in their 50s are likely to have a breast cancer death prevented by regular mammography). The absolute benefit will be higher for women with a higher absolute risk of breast cancer, underscoring the importance of identifying higher-risk women. Especially for average-risk women, decisions to undergo regular mammography screening must also consider the harms of mammography—most notably the possibility of overdiagnosis and resultant overtreatment (age-specific estimates of which are lacking) and also the risks of false positives and unnecessary biopsies (known to be greater in younger women and women screened more frequently).
Despite the vast literature on screening mammography, the evidence needed to help women make decisions remains incomplete. "

For now, I would recommend continuing with yearly mammograms until the age of 75; and considering dropping to every second year after about age 60. But hard evidence is lacking and, as we develop better mammography methods it may be difficult to really know what to do.