December 12, 2012
Common Diabetes Drug Shows Promise
in Ovarian Cancer Treatment
Rochester, MN—The latest drug showing promise against ovarian cancer can be found in millions of medication cabinets in the United States and can be purchased for less than $10 a month at many pharmacies.

In a new study, researchers from the Mayo Clinic found that diabetic patients with ovarian cancer who took the drug metformin had a better survival rate than patients who did not take it. Metformin is considered first-line treatment for diabetes and pre-diabetes in the vast majority of clinical guidelines and, therefore, is used by many of the more than 20 million Americans with type 2 diabetes.

For the study, published recently in the journal Cancer, researchers compared the survival of 61 patients with ovarian cancer taking metformin and 178 patients who were not taking metformin. After 5 years, 67% of the patients who took metformin were surviving, compared with 47% of those who did not take the medication. Taking into account analysis of factors such as body mass index, the severity of the cancer, type of chemotherapy and quality of surgery, patients taking metformin were nearly four times likelier to survive, compared with those not taking the medication, according to the research.

Study authors report that, using 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.

“Our study demonstrated improved survival in women with ovarian cancer that were taking metformin,” said co-author Sanjeev Kumar, M.B.B.S., a Mayo Clinic gynecologic oncology fellow. “The results are encouraging, but as with any retrospective study, many factors cannot be controlled for us to say if there is a direct cause and effect. Rather, this is further human evidence for a potential beneficial effect of a commonly used drug which is relatively safe in humans. These findings should provide impetus for prospective clinical trials in ovarian cancer.”

Study authors called for large-scale randomized trials to determine metformin’s effectiveness in treating ovarian cancer.

Metformin’s benefits may not be limited to ovarian cancer, however. A meta-analysis published earlier this year explained, “A growing body of evidence has suggested that metformin potentially reduces the risk of cancer. Our objective was to enhance the precision of estimates of the effect of metformin on the risk of any-site and site-specific cancers in patients with diabetes.”

The study, which appeared in the online journal PLOS One, concluded that “the use of metformin in diabetic patients was associated with significantly lower risks of cancer mortality and incidence.” The authors point out, however, that their analysis was primarily based on observational studies and that long-term randomized trials would be necessary to confirm the potential benefit.

U.S. Pharmacist Social Connect