Breast cancer risk in women with radial scars in benign breast biopsies

Background: The risk for subsequent breast cancer in women diagnosed with radial scar lesions (RS) on benign breast biopsy remains controversial. We studied the relative risk of radial scar lesions in a large cohort of patients with benign breast disease (BBD). Methods: Radial scars were identified in a BBD cohort of 9,262 patients biopsied at Mayo Clinic between 1967 and 1991. Radial scar lesions were classified as proliferative disease without atypia (PDWA) unless atypia was present (classified as atypical hyperplasia [AH]). The observed number of breast cancers developing among those with RS was compared to that expected in the general population using standardized incidence ratios (SIRs, mean follow-up interval 17 years). Results: RS were identified in 439 (4.7%) of the cohort members; 382 (87.0%) contained one RS, 42 (9.6%) contained two, 9 (2.0%) contained three, and 6 (1.4%) contained four or more. The majority of RS (356, 82.4%) were less than 5.0 mm in diameter; 60 (13.9%) were 5.0–9.9 mm, and 16 (3.7%) were 10.0 mm or greater. The relative risk for women with PDWA and RS was 1.88 (95% CI, 1.36–2.53), no different than PDWA without RS [relative risk 1.57 (95% CI, 1.37–1.79) (P = 0.29)]. Women with atypical hyperplasia and RS (n = 60) had a relative risk of 2.81 (95% CI, 1.29–5.35), while those with atypia but without RS had a relative risk of 3.97 (95% CI, 2.99–5.19). Conclusions: RS imparts no increased breast cancer risk above that of PDWA or AH without RS.