Interdependence of radial scar and proliferative disease with respect to invasive breast carcinoma risk in patients with benign breast biopsies

BACKGROUND. Radial scars (RS) are benign breast lesions that have been implicated as independent risk factors for invasive breast carcinoma (IBC). METHODS. A retrospective cohort study of 9556 women who underwent biopsy between 1950-1986 and enrolled in the Nashville Breast Cohort was performed to investigate the association between RS in a benign breast biopsy and the risk of IBC. The risk associated with RS and coexistent proliferative disease (PD) was assessed adjusting for age at biopsy using a Cox hazards regression analysis with time-dependent covariates. RESULTS. RS were identified in 880 women (9.2%). The average follow-up time was 20.4 years. Sixty-two women (7.0%) with RS developed IBC compared with 5.5% of controls. The relative risk of IBC associated with RS was 1.82 (95% confidence interval [95% CI], 1.2-2.7) at 10 years. Restricting the analysis to women age > 49 years increased the risk to 2.14 (95% CI, 0.6-2.8). These risks decreased with increasing years Of follow-up. Approximately 92% of women with RS also had PD, but RS were present in only 1.3% of biopsies without PD. Analyses stratifying relative risk with regard to PD found RS to minimally elevate the relative risk of subsequent IBC. CONCLUSIONS. RS in the absence of PD is uncommon. Although the presence of RS in a benign breast biopsy mildly elevates the risk of IBC risk, the current analysis indicated that this risk can be largely attributed to the category of coexistent PD. In women with both RS and atypical hyperplasia, recommendations for interventions beyond biopsy should be based on the extent of atypical hyperplasia.