Ingham 2013.

Methods	Retrospective cohort
Participants	691 female BRCA1/2 mutation carriers without breast or ovarian cancer at time of family referral to one Genetic Medicine center between February 1980–December 2011 (346 BRCA1, 345 BRCA2) 457 did not have any risk‐reducing surgery; 58 had BRRM only, 68 had both BRRM & RRSO, 108 RRSO only
Interventions	BRRM & RRSO
Outcomes	Survival
Notes	Female first‐degree relatives (FDRs) without predictive genetic testing who otherwise met eligibility criteria were also included
Risk of bias
Bias	Authors' judgement	Support for judgement
Free of selection bias?	Low risk	Patients identified from Genetic Medicine database, genetic status confirmed, plus female first‐degree relatives who had not been tested but met “alive & unaffected at time of family referral” to control for testing bias
Free of performance bias?	Low risk	Used medical records from Manchester Genetic Medicine database. Also used “family files” or records at North West Cancer Intelligence Service for cancer breast confirmation or National Health Service records
Free of detection bias?	Low risk	Used medical records from Manchester Genetic Medicine database. Also used “family files” or records at North West Cancer Intelligence Service for cancer breast confirmation or National Health Service records
Free of attrition bias?	Low risk	Retrospective analysis so no dropouts; women censored at date of last follow‐up (last contact with genetics dept. or other NHS service) or date of death