1-Sample analysis of the proportion of expected cancers (based on germline mutation, menopausal status, and age) observed in follow-up (95% CI using the Wilson method) and ratio of the proportion of cancers prevented in after RRES until DO compared with RRSO (95% CI using a nonparametric bootstrap); for both estimators, the expected cancer incidence without surgery is estimated using meta-analysis data on BRCA1/2 penetrance by age. The gene discussed is BRCA1; the disease is cancer.