A new research suggests that an anti-diabetic drug, metformin, may lower lung cancer risk in diabetic nonsmokers.
The research at the Kaiser Permanente Division of Research in Oakland, California, suggest that metformin may prevent cancer, but the data from human studies, however, are conflicting.
Metformin use was not associated with lower lung cancer risk overall, however, the risk was 43 percent lower among diabetic patients who had never smoked and the risk appeared to decrease with longer use.
Nonsmokers who used metformin for five years or longer had a 52 percent reduction in lung cancer risk, but this finding was not statistically significant.
Metformin use for five or more years was associated with a 31 percent decrease in the risk for adenocarcinoma, the most common type of lung cancer diagnosed in nonsmokers, and an 82 percent increase in the risk for small-cell carcinoma, a type of lung cancer often diagnosed in smokers, but neither of these findings was statistically significant.
In an interview, researcher Lori Sakoda said that metformin use was not associated with lung cancer risk when they looked at all patients with diabetes.
Sakoda added that their results suggest that risk might differ by smoking history, with metformin decreasing risk among nonsmokers and increasing risk among current smokers, suggesting that the risk associated with metformin might differ by smoking history were unexpected.
Sakoda added that additional large, well-conducted studies are needed to clarify whether metformin may be used to prevent lung or other cancers, particularly in specific subpopulations, such as nonsmokers.
The study appears in Cancer Prevention Research, a journal of the American Association for Cancer Research.