Breast cancer diagnosis by mammography is an important step in detection, but overdiagnosis can also be an issue. Researchers find that overdiagnosis is fairly common.
Breast cancer mammography screenings can lead to screen-detected breast cancer that, if not detected, would not have caused any signs or symptoms during the patient’s lifetime. There is no consensus about how often this type of overdiagnosis occurs, or what costs it may have. This article, published in the Annals of Internal Medicine, estimates the rate of breast cancer overdiagnosis in mammography practice, specifically as it relates to the detection of nonprogressive cancer.
This study relied on data from women aged 50 to 74 at the time of their first mammography screening, between 2000 and 2018. The cohort included 35,986 women, 82,677 mammograms, and 718 breast cancer diagnoses. Among all preclinical cases, 4.5% were estimated to be nonprogressive. In a program of biennial screening, 15.4% of cancer cases were estimated to be overdiagnosed, with 6.1% related to detecting indolent preclinical cancer, and 9.3% to detecting progressive cancer in women who would have died of unrelated causes prior to clinical diagnosis.
The design of this article relied on Bayesian inference of the natural history of breast cancer, using both individual screenings and diagnosis records. A combination of a fitted natural history model with life-table data was used to predict the rate of overdiagnosis among screen-detected cancer under a biennial screening program. The authors conclude that about 1 in 7 cases of screen-detected cancer is overdiagnosed in women 50 to 74 years of age. They note that this metric should be used to inform decision-making about the consequences of mammography screening.
Reference
Ryser, M. D., Lange, J., Inoue, L. Y. T., O’Meara, E. S., Gard, C., Miglioretti, D. L., . . . Etzioni, R. B. (2022). Estimation of Breast Cancer Overdiagnosis in a U.S. Breast Screening Cohort. Ann Intern Med, 175(4), 471-478. https://doi.org/10.7326/m21-3577
Ryser, M. D., Lange, J., Inoue, L. Y., O’Meara, E. S., Gard, C., Miglioretti, D. L., … & Etzioni, R. B. (2022). Estimation of breast cancer overdiagnosis in a US breast screening cohort. Annals of internal medicine, 175(4), 471-478.
