According to a recent study, non-smokers with a diagnosis of diabetes who used the drug metformin may have a decreased risk of lung cancer. The study entitled “Metformin Use and Lung Cancer Risk in Patients with Diabetes” was recently published in the journal Cancer Prevention Research.
Recent observational and laboratory studies have produced inconsistent results on the relationship between the use of metformin and lung cancer risk. To further examine this relationship, researcher Lori Sakoda from the Kaiser Permanente Northern California along with colleagues retrospectively assessed a total of 47,351 patients with diabetes aged 40 years and older. The assessment was conducted between 1994 and 1996 through a health-related survey, and information about diabetes medication was collected from electronic pharmacy records. In this sample, 46% of the participants were defined as “ever-users” of the drug metformin.
After a follow-up of 15 years (1997 to 2012), a total of 747 patients were diagnosed with lung cancer. Data analysis revealed no association with duration, dose, or recency of metformin use and overall lung cancer risk.
Furthermore, the research team found that those patients with diabetes that never smoked were at lower risk of lung cancer (43%), and the risk continued to decrease with prolonged use of metformin. However, these results were not statistically significant. Longer use of metformin was associated with lower adenocarcinoma risk (31%), but with higher risk for small carcinoma (82%). However, once more, these findings did not reach statistical significance.
Based on these results, the research team suggests there is insufficient evidence that metformin use affects overall lung cancer risk, and sees the need for further studies to assess these results.
In a recent news release Dr. Sakoda stated, “Metformin use was not associated with lung cancer risk when we looked at all patients with diabetes. However, our results suggest that risk might differ by smoking history, with metformin decreasing risk among nonsmokers and increasing risk among current smokers. Our results suggesting that the risk associated with metformin might differ by smoking history were unexpected. 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.”