The influence of family history on breast cancer risk in women with biopsy-confirmed benign breast disease: Results from the nurses' health study

BACKGROUND. An association between histologic category of benign breast disease (BBD) and breast cancer risk has been well documented. However, the influence of a positive family history (FH) on breast cancer risk among women with biopsy-confirmed BBD is less certain. METHODS. The authors conducted a nested case-control study of BBD and breast cancer risk among 2005 women who were enrolled in the Nurses' Health Study. Cases were women with breast cancer who had a previous benign breast biopsy (n = 395 women). Controls were women who also had previous biopsy-confirmed BBD but were free from breast cancer at the time the corresponding case was diagnosed (n = 1610 women). BBD slides were reviewed and categorized as either nonproliferative lesions, proliferative lesions without atypia, or atypical hyperplasia (AH). RESULTS. Compared with women who had nonproliferative lesions and no FH, women who had proliferative lesions without atypia and a positive FH had a higher breast cancer risk (odds ratio [OR], 2.45; 95% confidence interval [95% CI], 1.61-3.70) than women with no FH (OR, 1.51; 95% CI, 1.12-2.06; P = .07). Among women who had AH, the OR for the development of breast cancer was 4.38 (95% CI, 2.93-6.55) for those with no FH and 5.37 (95% CI, 3.01-9.58) for those with a positive FH (P = .57). There was no significant interaction between the type of BBD and FH (P = .74). CONCLUSIONS. A positive FH of breast cancer slightly increased the breast cancer risk among women who had proliferative lesions without atypia. The increase in risk of breast cancer associated with FH was not significant among women who had AH.