title: Do breast cancer survivors benefit from prophylactic removal of uterus and ovaries? A population-based data linkage replication study.
abstract: OBJECTIVE
  Our previous population-based research found prophylactic surgery (hysterectomy and bilateral salpingo-oophorectomy [BSO]) halved the mortality risk for premenopausal breast cancer patients. Here we aim to replicate findings in a Western Australia dataset.
  
  
  METHODS
  Data from the Western Australia Cancer Registry of 15 395 women 20-79 years diagnosed with primary breast cancer (1997-2011) was categorized into four groups: neither hysterectomy nor BSO, hysterectomy only, BSO only, or hysterectomy + BSO. We fitted flexible parametric breast cancer-specific and overall survival models with 95% confidence intervals (also known as Royston-Parmar models) to assess the impact of prophylactic surgery.
  
  
  RESULTS
  A total of 12 630 (82.0%) patients had no surgery, 1799 (11.7%) had a hysterectomy only, 337 (2.2%) had BSO only and 629 (4.1%) had both a hysterectomy and BSO. For all-causes mortality, unadjusted 10-year survival was highest for women who had either a hysterectomy + BSO (84.7%) or a hysterectomy only (84.2%). After adjusting for covariates, the survival advantage compared to women without any surgery remained significant for the hysterectomy only group (hazard ratio [HR] = 0.89; 95% confidence interval [CI], 0.81-0.98; P = 0.02). A similar pattern emerged in breast cancer-specific survival with significantly improved survival for women who had a hysterectomy only (HR = 0.83; 95% CI, 0.74-0.94; P = 0.003). However, for non-breast cancer-related survival, having a BSO alone increased risk of death (HR = 1.83; 95% CI, 1.14-2.93; P = 0.01).
  
  
  CONCLUSIONS
  We observed significantly improved overall and breast cancer-specific survival among women who had a hysterectomy only, but increased non-breast cancer-related risk after BSO only. Breast cancer patients must weigh up pros and cons of prophylactic surgery.
authors.affiliation: School of Medicine, The University of Queensland, Royal Brisbane and Women's Hospital, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Andreas
authors.initials: A
authors.lastname: Obermair
authors.affiliation: Cancer Council Queensland, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Danny
authors.initials: D
authors.lastname: Youlden
authors.affiliation: Cancer Council Queensland, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Baade
authors.affiliation: Institute for Health and Biomedical Innovation, School of Public Health, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Monika
authors.initials: M
authors.lastname: Janda
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000601:surgery*; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008875:Middle Aged; D010052:Ovariectomy; D010053:Ovary; D016016:Proportional Hazards Models; D012042:Registries; D017741:Survivors; D055815:Young Adult
keywords: breast cancer; ovarian cancer; prophylactic surgery; survival; uterine cancer