title: Metformin intake is associated with better survival in ovarian cancer: a case-control study.
abstract: BACKGROUND
  The objective of this case-control study was to identify any association of metformin intake with the survival of patients with ovarian cancer.
  
  
  METHODS
  In this retrospective case-control study, women with ovarian cancer who received metformin (cases) were compared with women with ovarian cancer who did not receive metformin (controls). A 2-layered analysis was conducted. In preliminary analysis, all cases (the OC cohort) were compared with controls at a 1:2 ratio. Subsequently, in definitive analysis, only patients who had epithelial ovarian cancer (the EOC cohort) were compared with controls at a 1:3 ratio. In the EOC cohort, cases were matched with controls for age (±5 years), International Federation of Gynecology and Obstetrics stage, and residual disease. Prognostic variables and disease specific survival were compared using chi-square tests, the Kaplan-Meier (log-rank) method, and Cox proportional hazards analysis.
  
  
  RESULTS
  In a preliminary analysis of the OC cohort (72 cases and 143 controls), cases had better survival (5-year disease-specific survival for cases vs controls, 73% vs 44%; P = .0002). In the definitive analysis of the EOC cohort (61 cases and 178 controls), the distribution of age, disease stage, optimal cytoreduction, serous histology, and platinum chemotherapy remained similar between cases and controls (P > .05). Despite these similarities, cases had significantly better survival (5-year disease-specific survival for cases vs controls, 67% vs 47%; P = .007). On multivariate analysis, metformin remained an independent predictor of survival (hazard ratio, 2.2; 95% confidence interval, 1.2-3.8; P = .007) after controlling for disease stage, grade, histology, chemotherapy, body mass index, and surgical cytoreduction.
  
  
  CONCLUSIONS
  The results of this study indicated an association of metformin intake with survival in patients with ovarian cancer. The receipt of metformin was associated with better survival, and the authors concluded that metformin is worthy of clinical trials in ovarian cancer.
authors.affiliation: Department of Gynecologic Surgery, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Kumar
authors.forename: Alexandra
authors.initials: A
authors.lastname: Meuter
authors.forename: Prabin
authors.initials: P
authors.lastname: Thapa
authors.forename: Carrie
authors.initials: C
authors.lastname: Langstraat
authors.forename: Shailendra
authors.initials: S
authors.lastname: Giri
authors.forename: Jeremy
authors.initials: J
authors.lastname: Chien
authors.forename: Ramandeep
authors.initials: R
authors.lastname: Rattan
authors.forename: William
authors.initials: W
authors.lastname: Cliby
authors.forename: Viji
authors.initials: V
authors.lastname: Shridhar
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage; D000077216:Carcinoma, Ovarian Epithelial; D016022:Case-Control Studies; D015331:Cohort Studies; D048909:Diabetes Complications / Q000188:drug therapy / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D008687:Metformin / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality*; D010051:Ovarian Neoplasms / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality*; D012189:Retrospective Studies; D016019:Survival Analysis; D015996:Survival Rate
chemical_list: D000970:Antineoplastic Agents; D007004:Hypoglycemic Agents; D008687:Metformin