By Joseph E. Scherger, MD, MPH
Core Faculty, Eisenhower Health Family Medicine, Residency Program, Eisenhower Health Center, La Quinta, CA; Clinical Professor, Keck School of Medicine, University of Southern California, Los Angeles
SYNOPSIS: Overdiagnosis of breast cancer from mammography is common in women age 70 years and older and increases with age. The use of mammography in women older than age 70 years does not reduce breast cancer deaths.
SOURCE: 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.
This study was funded by the National Cancer Institute and was conducted by investigators in general internal medicine at Yale School of Medicine along with assistance from the Yale Cancer Center and the Yale School of Public Health. The study method was a retrospective cohort analysis of 54,635 women older than 70 years of age who continued mammogram screening. They were followed for 15 years for the incidence of positive results, diagnosis of breast cancer, and mortality.
The study subjects were stratified into women aged 70-74 years, 75-84 years, and older than 85 years. Women who were screened were compared with women who were not screened. For women aged 70-74 years, breast cancer was diagnosed in 6.1 cases per 100 screened women and in 4.2 cases per 100 unscreened women. An estimated 31% of breast cancer in this group was potentially overdiagnosed. For women aged 75-84 years, 4.9 per 100 screened women were diagnosed with breast cancer compared with 2.6 per 100 unscreened women, for a potential 47% of cases overdiagnosed. For women aged 85 years and older, the incidence of breast cancer was 2.8 per 100 among screened women and 1.3 per 100 among unscreened women, with a 54% potential incidence of overdiagnosis.
There was no survival benefit to mammography screening in any of these age groups. The study did not address potential harms to women because of screening and overdiagnosis.
COMMENTARY
Overdiagnosis of breast cancer from screening mammography has been a known problem, and the risk of screening should be weighed against the benefits.1,2 The goals of breast cancer screening are earlier diagnosis and reduced mortality. The contribution of this study is that breast cancer screening with mammography results in an increasing rate of overdiagnosis in women aged 70 years and older with no mortality benefit.
The American Cancer Society recommends continued mammography screening if life expectancy is more than 10 years.3 The American College of Physicians recommends discontinuing screening at age 75 years and older if life expectancy is less than 10 years.4
Although the care of patients should be individualized based on their health and life expectancy, this study suggests that these guidelines be reconsidered and that screening could be stopped at age 70 in most women.
REFERENCES
- Walter LC, Schonberg MA. Screening mammography in older women: A review. JAMA 2014;311:1336-1347.
- Garcia-Albeniz X, Hernan MA, Logan RW, et al. Continuation of annual screening mammography and breast cancer mortality in women beyond age 75 years: A cost effectiveness analysis. Ann Intern Med 2020;172:381-389.
- Oeffomger KC, Fontham ETH, Etzoni R, et al. Breast cancer screening for women at average risk: 2015 guideline update from the American Cancer Society. JAMA 2015;314:
1599-1614. - Qaseem A, Lin JS, Mustafa RA, et al. Clinical Guidelines Committee of the American College of Physicians. Screening for breast cancer in average-risk women: A guidance statement from the American College of Physicians. Ann Intern Med 2019;170:547-560.