Subsequent breast cancer risk after benign breast biopsy in racially diverse women: Siteman Cancer Center.

backgroundThe association between histological subtypes of benign breast disease and subsequent breast cancer risk in the postmammography era of increased benign breast disease detection requires continued study to inform the clinical management of high-risk women.

methodsWe identified a cohort of 8915 women diagnosed with histologically confirmed benign breast lesions between 2010 and 2023 from the Joanne Knight Breast Health Center in St. Louis. Risk of subsequent breast events after a benign breast biopsy was assessed with Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs).

resultsWithin a median follow-up of 6.5 years, 363 women developed breast cancer. The cohort was 63.7% White, 32.4% Black, and 3.9% Asian race. Breast cancer risk increased across subtypes of benign breast disease, from proliferative disease without atypia to atypical hyperplasia, with atypical hyperplasia risk modified by time since biopsy and menopause. Compared with women with nonproliferative disease, age-adjusted risk for breast cancer was 1.69 for proliferative disease without atypia (HR = 1.69, 95% CI = 1.35 to 2.12) and 2.78 for atypical hyperplasia (HR = 2.78, 95% CI = 2.01 to 3.85; P < .0001 for trend). Risk estimates attenuated but remained similar in fully adjusted models. Risks associated with benign breast disease subtypes were similar for Black and White women, but Black women with atypical hyperplasia had greater risk of breast cancer since recent biopsy (≤4 years) and during the premenopausal period (P = .033 for heterogeneity).

conclusionBreast cancer risk increases with the degree of epithelial proliferation, highest in atypical hyperplasia, amplified by recent biopsy and premenopause, particularly in Black women, consistent with the excess risk seen after ductal carcinoma in situ in this group.