Hartmann 1999a.

Methods	Case series and retrospective cohort study (1 paper, 2 studies)
Participants	Family history/risk ‐ all with a family history of BC were included
Interventions	BRRM (subcutaneous or total) = 639 High risk = 214 Comparison group: sisters without BRRM = 403 Moderate risk = 425 Comparison group: statistically modeled group based on Gail model presuming no BRRM
Outcomes	BC incidence BC mortality
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Free of selection bias?	High risk	Study did not control for other important preventive measures besides RRM that may have been used by this population including oophorectomy and chemoprevention.
Free of performance bias?	Low risk	Chart review identified patients who had BRRM at the Mayo Clinic
Free of detection bias?	Low risk	Chart review provided incidence and survival information.
Free of attrition bias?	Low risk	14 (2%) eligible women could not be found, and 32 women (5%) refused to participate but their medical records were available.