Concurrent Metformin Use and Survival Among Finnish Non-Small Cell Lung Cancer Patients Treated With EGFR TKIs
Abstract Purpose Many studies have shown correlation between metformin use and lower incidence and improved outcomes of lung cancer. We investigated the potential association between metformin use and survival among Finnish non-small cell lung cancer (NSCLC) patients treated with EGFR TKIs. Methods Nationwide registries were utilized to identify all the patients with use of EGFR TKIs in NSCLC between 2011–2016, and 1242 patients were included in further analyses. Data related to cancer, survival, and drug purchases were combined with personal identity codes. Concurrent use of diabetes medications was defined as their purchase +/-120 days from the first purchase of EGFR TKI. The impact of diabetes medication use was investigated separately in the whole and in the EGFR mutant type cohort (n = 481). Results Concurrent metformin use was found in 10 % (n = 124) and use of other diabetes medication in 5 % (n = 60) of the patients. In the whole patient cohort, metformin use did not associate with survival but in the EGFR mutant type cohort a non-significant trend for higher mortality was found (HR 1.42, 95% CI 0.99–2.02). Metformin use associated also with a shorter EGFR TKI treatment duration (HR 1.26, 95 % CI 1.04–1.52). The use of other diabetes medication than metformin did not associate with survival or EGFR TKI treatment duration. Conclusion Concomitant metformin use associated with a shorter EGFR TKI treatment duration, however, no statistically significant correlation with survival was found. Ethnicity, comorbidities, and metformin dosage may influence on the associations found between metformin use and EGFR TKI treatment responses.