Background: A number of observational studies examined the association between metformin therapy
and ovarian cancer survival outcomes, but the results are inconsistent.
Objective: The study aimed to investigate the effect of metformin on survival for ovarian cancer patients.
Method: PubMed, Embase and Web of Science databases were searched for relevant studies from the inception to
June 11, 2019. The strength of the relationship was assessed using summary of hazard ratios (HRs) with corresponding
95% confidence intervals (CI). Statistical analyses were carried out using the random-effects model.
Results: Totally, 6 retrospective cohort studies involving 2,638 ovarian cancer patients were included. Metformin
was not associated with improved overall survival (HR=0.78, 95% CI 0.54-1.12, P=0.175, I2= 61.6%) and disease-
free survival (HR=0.49, 95% CI 0.20-1.17, P=0.106, I2=82.1%) in ovarian cancer patients compared to nonmetformin
Conclusion: The current study provides preliminary evidence that metformin may not be associated with a survival
benefit for ovarian cancer patients. More studies with rigorous designs are needed.