Koskenvuo 2014.

Methods	Retrospective cohort
Participants	52 women in cohort of 136 BRCA1/2 mutation carriers who had RRM surgery and/or were followed up at the Helsinki University Central Hospital (HUCH)
Interventions	RRM
Outcomes	Complications BC incidence
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Free of selection bias?	Low risk	Included all BRCA1/2 mutation carriers who had follow‐up or surgery at HUCH from January 1997–March 2010
Free of performance bias?	Low risk	Used patient records from Breast Surgery Unit and Dept. of Plastic Surgery
Free of detection bias?	Low risk	Used patient records from Breast Surgery Unit and Dept. of Plastic Surgery
Free of attrition bias?	Low risk	Excluded men, those followed‐up or treated at other hospitals, mutation carriers who previously had bilateral treatment mastectomy, participants diagnosed during preoperative imaging