Population-based cohort study of breast cancer incidence after a false-positive mammography result in Sweden

False-positive mammography results are common. A population-based cohort study in Sweden examined risk of developing breast cancer among 45,213 women with a first false-positive mammography result in 1991-2020 and 452,131 controls matched on age, calender year of mammography, and screening history (no previous false-positive result. The 20-year cumulative incidence of breast cancer was 11.3% among women with a false-positive result versus 7.3% among those without (HR 1.61; 95% CI 1,54-1,68). The corresponding HRs were higher among women aged 60 to 75 years at the examination (HR 2.02; 95% CI 1.80-2.26) and those with lower mammographic breast density (4.65; 2.61-8.29). Cancer after a false-positive result were more likely to be detected at the ipsilateral side of the false-positive result (HR 1.92; 95% CI 1.81- 2.04) and were more common during the first 2 years of follow-up (2.57; 2.33-2.85). Women with a false-positive result had a higher rate of breast cancer death than those without (HR 1.84; 95% CI 1.57-2.15). The authors conclude that breast cancer awareness should be emphasized long term for women with a false-positive mammography result.