Sanjeev Kumar of the Mayo Clinic College of Medicine and colleagues analyzed the records of 239 women who had ovarian cancer and compared them to those who had taken metformin with those who had not.
The study, published online in the journal Cancer, found 67 percent of those who took the drug had not died from ovarian cancer within five years, compared to 47 percent of those who didn't take the drug.
Even after adjusting for stage, treatments received and the subtype of ovarian cancer, the data showed that ovarian cancer patients taking metformin had more than double the survival than those who didn't take the medication, Kumar said.
Still, researchers need to do a lot more study before they can say for sure that metformin is safe and effective for this use, because is not currently available as an ovarian cancer treatment, the study said.
All the women in the study who took the drug were already taking it to treat their diabetes, Kumar explained.