Expert Commentary

Do screening mammograms in women aged 70 and older improve stage at diagnosis or breast cancer–specific mortality?

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No. In an observational study that used Medicare claims data matched with the SEER (Surveillance, Epidemiology, and End Results) database, the incidence of overdiagnosis, defined as finding a cancer that would not have caused clinical problems during a person’s lifetime, increased with age (from 31% for women aged 70–74 to 54% for women aged 85 and older). There was no difference in the stage of diagnosed cancers and no statistically significant reduction in breast cancer–specific mortality between people who continued mammogram screening and those who did not.


 

References

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Richman IB, Long JB, Soulos PR, et al. Estimating breast cancer overdiagnosis after screening mammography among older women in the United States. Ann Intern Med. 2023;176:1172-1180. doi:10.7326/M23-0133

EXPERT COMMENTARY

A screening test is performed to detect potential health disorders or diseases in people who do not have any symptoms of disease. The goal of screening is to detect the condition early enough to treat it most effectively, and ultimately to decrease morbidity and mortality related to the disease. Overdiagnosis refers to the finding of a cancer that would not have caused clinical problems during a person’s lifetime.

Current guidelines for the early detection of breast cancer vary considerably, including recommendations for what age to initiate screening, the cadence of screening (annual or biannual), the use of ancillary screening for people with dense breasts, and importantly the upper age limit for which screening is advised. The US Preventive Services Task Force recommends continuing screening to age 74. The American Cancer Society suggests ongoing screening if life expectancy is estimated at more than 10 years, and the American College of Physicians recommends stopping screening at age 75, or younger if life expectancy is less than 10 years. The American College of Obstetricians and Gynecologists states that women at average risk of breast cancer should continue screening mammography until at least age 75.

Overdiagnosis is a difficult concept for clinicians to understand let alone explain to our patients. Recently, Richman and colleagues published the results of their study aimed at estimating overdiagnosis associated with breast cancer screening among older women.1 As Dr. Otis Brawley, former Chief Medical and Scientific Officer of the American Cancer Society and current Distinguished Professor of Oncology and Epidemiology at Johns Hopkins University, states in the editorial that accompanies the study by Richman and colleagues, “Some tumors are not destined to grow, spread, and kill due to their genomics or their microenvironment. A second type of overdiagnosis involves small tumors that do have the potential to grow but will not grow fast enough to bother the patient within their natural lifetime.”2

Although screening mammography in older women results in frequent false positives that require additional imaging as well as biopsies, we have become more aware of the potential of overdiagnosis as an important downside of screening mammography in an elderly population.

Continue to: Details of the study...

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