Background :
Screening mammography can lead to overdiagnosis , that is, breast cancer detected by screening that would not have caused symptoms or signs in the rest of your life. There is no consensus on the frequency of breast cancer overdiagnosis.
Aim:
To estimate the rate of breast cancer overdiagnosis in contemporary mammography practice that represents the detection of non-progressive cancer.
Design:
Bayesian inference of the natural history of breast cancer using individual screening and diagnosis records, allowing for non-progressive preclinical cancer. Combining a fitted natural history model with life table data to predict the rate of overdiagnosis among cancer detected by biennial screening.
Setting:
Breast Cancer Surveillance Consortium (BCSC) Facilities.
Participants:
Women aged 50 to 74 at their first mammogram between 2000 and 2018.
Measurements:
Screening mammograms and interval or screening-detected breast cancer.
Results:
The cohort included 35,986 women , 82,677 mammograms, and 718 breast cancer diagnoses.
Among all preclinical cancer cases , 4.5% (95% uncertainty interval [UI], 0.1% to 14.8%) were estimated to have not progressed .
In a biennial screening program from ages 50 to 74, 15.4% (IU, 9.4% to 26.5%) of screening-detected cancer cases were estimated to be overdiagnosed, with 6. 1% (IU, 0.2% to 20.1%) due to detecting indolent preclinical cancer and 9.3% (IU, 5.5% to 13.5%) due to detecting progressive preclinical cancer in women who would have died from an unrelated cause before clinical diagnosis.
Limitations:
Exclusion of women with first mammography screen outside of BCSC.
Conclusion: Based on an authoritative data set of the US population, the analysis projected that among women ages 50 to 74 who are screened every two years, about 1 in 7 cases of cancer detected by screening tests is overdiagnosed. This information clarifies the risk of breast cancer overdiagnosis in contemporary screening practice and should facilitate shared and informed decision-making about mammography screening. |
Primary funding source: National Cancer Institute.
