LOS ANGELES – A growing body of evidence suggests that the widely used diabetes drug metformin can reduce the risk of cancer, researchers said Wednesday.
A study in mice exposed to tobacco carcinogens, published Wednesday, shows that the drug can reduce the development of lung tumors by as much as 70 percent, and results from a small clinical trial in Japan suggest it can reduce rates of colorectal tumors in humans. The National Cancer Institute is now organizing a clinical trial to test the drug in people who smoke.
There is not yet enough evidence to recommend using the drug routinely for cancer prevention, but the evidence is strong enough that physicians and patients considering drug therapy for Type 2 diabetes might want to lean toward metformin because of its ancillary effects, researchers said.
The drug is particularly promising because unlike use of finasteride for preventing prostate cancer or tamoxifen for breast cancer, metformin appears to act across a broad spectrum of cancers, said Dr. Michael Pollak, a medical oncologist at McGill University in Montreal.
Metformin increases the sensitivity of cells to insulin. It is one of the most widely used diabetes drugs, with 40 million prescriptions written in the United States in 2008.