Sunday, March 22, 2020

Breast cancer screening is harmful after age 75

- Kenny Lin, MD, MPH

To increase acute care capacity during the COVID-19 pandemic, hospitals have suspended elective surgical procedures, and family medicine practices have postponed visits for preventive care and monitoring of stable chronic diseases - particularly in patients older than 70 years, whose risk of developing serious illness from SARS-CoV-2 contracted in a health care setting likely outweighs potential benefits. For example, women in this age group should cancel or postpone screening mammograms.

Even in the best of times, though, it's not known if screening mammography beyond 75 years of age is helpful or harmful. The U.S Preventive Services Task Force found insufficient evidence to assess the balance of benefits and harms of breast cancer screening after age 75, and decision tools have been developed to help women decide whether or not to continue to be screened, relying on limited evidence and the patient's predicted life expectancy. As the authors of a recent AFP editorial observed, though, discussing the clinical implications of life expectancy with older patients can be challenging and fraught with pitfalls.

Since it is unlikely that a randomized controlled trial of screening mammography in older women will be performed, researchers recently used observational data from the U.S. Medicare program to emulate such a trial in more than 1 million beneficiaries aged 70 to 84 years with a life expectancy of at least 10 years and no previous breast cancer diagnosis. The primary outcome was eight-year risk of breast cancer mortality.

While women age 70 to 74 years who continued to have screening mammograms had a 22 percent lower risk than those who stopped being screened, there was no mortality benefit for women who continued screening after age 75 years. Although guidelines already discourage screening for cancer in adults with a life expectancy of less than 10 years, this study suggested that stopping breast cancer screening after age 75 may be the right decision for all women, regardless of health status.