Meijers‐Heijboer 2001.

Methods	Prospective cohort study
Participants	139 women who had BRCA 1 or 2 mutations
Interventions	BRRM (simple total) = 76 Comparison group: close observation = 63 Close observation defined as monthly breast self‐examination, clinical breast examination every 6 months, and yearly mammography
Outcomes	BC incidence BC mortality
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Free of selection bias?	High risk	While the study authors controlled for some factors such as age and oophorectomy status, adjustment of other important factors was not reported.
Free of performance bias?	Low risk	Only women who tested positive for BRCA1/2 were invited to participate in BC surveillance program. Participants were those who had BRRM.
Free of detection bias?	Low risk	Vital status and the occurrence of cancer was extracted from the women’s medical files.
Free of attrition bias?	Low risk	No women were lost to follow‐up after BRRM