Metformin may lower cancer risk in people with Type 2 diabetes: study

WASHINGTON, June 25 (Xinhua) -- The commonly prescribed diabetes drug metformin reduces the overall cancer risk in people with Type 2 diabetes, according to a large review study presented Monday at The Endocrine Society's 94th Annual Meeting in Houston.

"Type 2 diabetes increases the risk for several types of cancer, " said lead author Diego Espinoza-Peralta, an endocrinologist with Mexico's National Institute of Medical Sciences and Nutrition in Mexico City. "Our findings suggest that the regular use of metformin -- a low-cost medication -- reduces this risk, compared with not taking metformin."

Espinoza-Peralta and colleagues conducted a systematic review and meta-analysis of reported studies that evaluated cancer risk in patients with Type 2 diabetes. They analyzed seven relevant studies that included more than 32,400 Type 2 diabetic patients who had no other known condition that increased their cancer risk.

The investigators found that the odds of getting any type of cancer was 38 percent less with daily continuous use of metformin than for those with no exposure to metformin. This risk reduction extended to certain types of cancers, specifically colon and breast cancer, which are among the cancers that studies have found to occur more often in people with Type 2 diabetes. There was no risk reduction, however, in pancreatic cancer, another type of cancer for which people with Type 2 diabetes are at increased risk.

Metformin, which is the standard recommended initial treatment of Type 2 diabetes, may protect against cancer because it regulates activity of an enzyme that suppresses cell growth, according to Espinoza-Peralta.