Zion 2003.

Methods	Retrospective cohort study
Participants	Family history/risk ‐ not reported
Interventions	1417 women who had BRRM or CRRM at 1 institution between 1960‐1993 BRRM = 593 with reconstruction CRRM = 506 with reconstruction BRRM = 39 without reconstruction CRRM = 279 without reconstruction
Outcomes	Physical morbidity
Notes	Zion 2000 reported on same CRRM participants in an abstract Some BRRM participants are the same as Hartmann 1999a
Risk of bias
Bias	Authors' judgement	Support for judgement
Free of selection bias?	Low risk	Reoperations compared only among implant reconstruction group and no reconstruction group, not autologous tissue reconstruction with less reoperation rate
Free of performance bias?	Low risk	Used patient survey with responses validated by medical records
Free of detection bias?	Low risk	Used medical records, Cox regression & Anderson‐Gill models to assess risk of reoperations
Free of attrition bias?	Low risk	92% of participants answered surveys, medical records available for all; no reason given for non‐responders

Key to abbreviations:
 AJCC ‐ American Joint Committee on Cancer
 BC ‐ breast cancer
 BCS ‐ breast conserving surgery
 BMI ‐ body mass index
 BRRM ‐ bilateral risk‐reducing mastectomy
 (B)RRSO ‐ (bilateral) risk‐reducing salpingo‐oophorectomy
 BSE ‐ breast self examination
 CBC ‐ contralateral breast cancer
 CRRM ‐ contralateral risk‐reducing mastectomy
 DCIS ‐ ductal carcinoma in situ
 ILC ‐ invasive lobular cancer
 LCIS ‐ lobular carcinoma in situ
 QoL ‐ quality of life
 RRM ‐ risk‐reducing mastectomy
 SF‐36 ‐ Short‐Form 35 Health Questionnaire