Metformin may decrease of lung cancer among nonsmokers with diabetes

the Oncology Nurse Advisor take:

According to a new study published in the journal Cancer Prevention Research, researchers have found that nonsmokers who took metformin to treat their type 2 diabetes had a decreased risk for developing lung cancer compared with those who did not take antidiabetic drug.

For the retrospective cohort study, researchers analyzed data from health-related surveys completed by 47,351 patients with diabetes between 1994 and 1996. By looking at electronic pharmacy records, researchers found that 46% of those had filled at least two prescriptions for metformin within a 6-month period, defined as ever-users. 

Results showed that during the 15-year follow-up, 747 patients developed lung cancer, 80 of whom were nonsmokers while 203 were current smokers. Researchers found no association between metformin use and a decreased overall lung cancer risk, but they observed a 43% risk reduction among patients with diabetes who had never smoked.

Although not statistically significant, researchers found that nonsmokers who took metformin for at least 5 years had a 52% decreased risk for developing lung cancer.

The findings suggest that metformin may decrease the risk of lung cancer in nonsmokers, but large, prospective studies are warranted to determine if metformin can decrease the risk of developing certain cancers.