Use of the oral antidiabetes drug metformin improved survival in women with ovarian cancer, according to the findings of a retrospective case-control study.

In a preliminary analysis of 72 women with ovarian cancer who received metformin (cases) and 143 women with ovarian cancer who were not taking this commonly used biguanide (controls), the metformin users had better 5-year disease-specific survival rates, at 73% compared with 44%.

The definitive analysis involved 61 cases with epithelial ovarian cancer and 173 controls. Despite the fact that the two groups were similar in terms of distribution of age, disease stage, optimal cytoreduction, serous histology, and platinum chemotherapy, cases had significantly better survival: The 5-year disease-specific survival for cases was 67%, compared with 47% for controls.

Metformin remained an independent predictor of survival after the researchers controlled for disease stage, grade, histology, chemotherapy, body mass index, and surgical cytoreduction, with users of the drug being up to nearly four times more likely to survive than nonusers.

Sanjeev Kumar, MBBS, a gynecologic oncology fellow at the Mayo Clinic in Rochester, Minnesota, and colleagues concluded in the journal Cancer that clinical trials exploring the effects of metformin use on ovarian cancer are warranted.