BRCA2 and breast cancer: Cox proportional hazards regression models, with HRT modeled as a time-varying covariate, evaluated the associations with BC risk while adjusting for potential confounders.<h4>Results</h4>A total of 919 women (mean [SD] age at RRBO, 47.6 [8.9] years) were included, of whom 496 had BRCA1 PV and 423 had BRCA2 PV.