Breast Cancer Chemoprevention in an Integrated Health Care Setting

PurposeNational guidelines encourage counseling high-risk women about pharmacologic breast cancer risk reduction. We evaluated the use of integrated health care data to identify and characterize breast cancer chemoprevention use. Chemoprevention included US Food and Drug Administration–approved use of tamoxifen and raloxifene and off-label use of aromatase inhibitors (AIs).Patients and MethodsUsing electronic medical and pharmacy records (EMRs) in the Kaiser Permanente Northern California health care system, we sampled cancer-free women age 35 to 69 years who used tamoxifen, raloxifene, exemestane, anastrozole, or letrozole from 2005 to 2013. Risk-benefit profiles were calculated for tamoxifen and raloxifene using published indices. The proportion of days covered was calculated from pharmacy records to assess adherence.ResultsAmong 90 chemoprevention users (confirmed with EMR review from a sample of 371 women), 74% used tamoxifen, 11% used raloxifene, and 13% used an AI. For tamoxifen and raloxifene users...