title: Tubal ligation and salpingectomy and the risk of epithelial ovarian cancer and borderline ovarian tumors: a nationwide case-control study.
abstract: OBJECTIVE
  According to the recent theories on the ovarian cancer origin, any protective effect of tubal ligation may vary with histologic subtype of ovarian cancer. Furthermore, bilateral salpingectomy may represent an opportunity for surgical prevention of serous ovarian cancer.
  
  
  METHODS
  Nationwide register-based case-control study.
  
  
  METHODS
  Denmark during 1982-2011.
  
  
  METHODS
  Cases were all Danish women diagnosed with epithelial ovarian cancer (n = 13 241) or borderline ovarian tumor (n = 3605) in the study period. Age-matched female population controls were randomly selected by risk set sampling. We required that cases and controls have no previous cancer and that controls have no previous bilateral oophorectomy.
  
  
  METHODS
  Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals, adjusting for potential confounders.
  
  
  METHODS
  Epithelial ovarian cancer and borderline ovarian tumors stratified according to histology.
  
  
  RESULTS
  Tubal ligation reduced overall epithelial ovarian cancer risk (odds ratios 0.87; 95% confidence interval 0.78-0.98). We observed significant risk variation according to histology (p = 0.003) with the strongest risk reductions associated with endometrioid cancer (odds ratios 0.66; 95% confidence interval 0.47-0.93) and epithelial ovarian cancer of "other" histology (odds ratios 0.60; 95% confidence interval 0.43-0.83). Tubal ligation was not associated with risk of borderline ovarian tumors. Finally, bilateral salpingectomy reduced epithelial ovarian cancer risk by 42% (odds ratios 0.58; 95% confidence interval 0.36-0.95).
  
  
  CONCLUSIONS
  We confirmed that tubal ligation reduces the risk of epithelial ovarian cancer and particularly endometrioid cancer. To our knowledge, this is the first observational publication to report on salpingectomy and ovarian cancer risk and our promising findings warrant further investigation.
authors.affiliation: Unit of Virus, Lifestyle and Genes, Danish Cancer Society Research Center, Copenhagen, Denmark.
authors.forename: Cecilie
authors.initials: C
authors.lastname: Madsen
authors.forename: Louise
authors.initials: L
authors.lastname: Baandrup
authors.forename: Christian
authors.initials: C
authors.lastname: Dehlendorff
authors.forename: Susanne K
authors.initials: SK
authors.lastname: Kjaer
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000077216:Carcinoma, Ovarian Epithelial; D016022:Case-Control Studies; D016001:Confidence Intervals; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D009375:Neoplasms, Glandular and Epithelial / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control; D016017:Odds Ratio; D010051:Ovarian Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control; D012042:Registries; D040242:Risk Reduction Behavior; D058994:Salpingectomy / Q000379:methods* / Q000706:statistics & numerical data; D013246:Sterilization, Tubal / Q000379:methods* / Q000706:statistics & numerical data
keywords: Ovarian cancer; borderline ovarian tumor; histologic subtype; salpingectomy; tubal ligation