Tsakiridis T, Pond GR, Wright J, et al. - This randomized clinical trial was conducted to determine if metformin could improve outcomes in locally advanced non–small cell lung cancer (LA-NSCLC) when administered concurrently with chemoradiotherapy and as consolidation treatment in patients with LA-NSCLC. Total 54 patients were randomized (26 in the experimental arm and 28 in the control arm). Findings demonstrated that worse treatment efficacy and increased toxic effects both resulted from the addition of metformin to chemoradiotherapy, vs combined modality therapy alone. In the metformin arm, the proportion of patients who had a failure event within 1 year (ie, locoregional disease progression, distant metastases, death, or withdrawal) was 69.2% vs 42.9% in the control arm. In the light of these findings, experts did not recommend metformin for LA-NSCLC patients who are candidates for chemoradiotherapy.