Diabetes Drugs Might Lower Risk of Lung Cancer

Researchers report that drugs used to treat diabetes may indeed both prevent and contain lung cancer. The findings, being presented Tuesday at the annual meeting of the American College of Chest Physicians in Vancouver, back up preliminary data that some diabetes medications might protect against tobacco-induced lung cancer. "Patients who did not develop lung cancer had a much higher chance of taking one of these medications than those who did develop lung cancer," said study author Dr. Peter Mazzone. "And those who did develop lung cancer were much less likely to have seen that cancer spread outside the chest and more likely to survive longer with one of these drugs."

Both metformin and the class of drugs known as thiazolidinediones (which includes Avandia and Actos) are used by tens of millions of Americans. A mouse study published in September found that metformin was associated with up to a 73 percent reduction in the number of tumors mice developed when they were given a common carcinogen found in tobacco. The mice had been genetically engineered to be susceptible to this kind of tumor. Epidemiological studies in humans have found similar effects. Metformin was originally marketed as Glucophage, but is now available as an inexpensive generic.

For this study, Mazzone and his colleagues reviewed and compared electronic medical records on 225 diabetics with lung cancer with a similar number of diabetic patients who did not have lung cancer, although both groups shared other risk factors such as age, smoking history and gender. "Forty-one percent of those with lung cancer had taken one of these medications at some point prior to developing the cancer, and 96 percent of all the controls had taken one of these medications in diabetic treatment," reported Mazzone, director of the lung cancer program at The Respiratory Institute at the Cleveland Clinic in Ohio.