Can Metformin Lower Lung Cancer Risk in Diabetic Patients?

Nonsmokers with diabetes who took metformin had a decrease in lung cancer risk, according to a study published in Cancer Prevention Research.

Lori Sakoda, PhD, MPH, research scientist at the Kaiser Permanente Division of Research in Oakland, CA, and colleagues conducted a retrospective cohort study of patients with diabetes (n=47,351) aged ≥40 years who completed a health-related survey between 1994–1996.

A total of 747 patients were diagnosed with lung cancer during the 15 year follow-up of which 80 were nonsmokers and 203 were smokers. The study found metformin use was not associated with a decrease in overall lung cancer risk but the risk was 43% lower among nonsmokers with diabetes with a further decrease with longer use.

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Nonsmokers who too metformin for at least five years had a 52% reduction in lung cancer risk, though it was not statistically significant. Patients who took metformin for at least five years had a 31% reduction in risk for adenocarcinoma, and an 82% increase in the risk for small-cell carcinoma; neither of these were not statistically significant.

The researchers concluded that more large, well-conducted studies are needed to assess whether metformin use may prevent lung cancer or other cancers in specific subpopulations.

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