Van Sprundel 2005.

Methods	Retrospective cohort study
Participants	Family history/risk ‐ BRCA1/2 mutation carriers
Interventions	148 BRCA1/2 mutation carriers (115 and 33, respectively) previously treated for unilateral BC at 2 medical centers CRRM = 79 Intense surveillance (monthly BSE, semi‐annual clinical breast exam, yearly mammography) = 69
Outcomes	All‐cause mortality BC mortality Disease‐free survival BC incidence
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Free of selection bias?	Low risk	All women who had unilateral BC and identified as BRCA1/2 mutations were included. However, all Dutch women with BRCA mutations are enrolled in surveillance; not clear if difference between those who chose CRRM and those who continued surveillance
Free of performance bias?	Low risk	All data extracted from medical files, operation and pathology reports
Free of detection bias?	Low risk	Did evaluate many factors as confounders, adjusted for effect of BRRSO
Free of attrition bias?	Low risk	Fairly short follow‐up, no attrition except death