Confirmation of the role of diabetes in the local recurrence of surgically resected non-small cell lung cancer

Purpose: We recently demonstrated that diabetes mellitus was an independent risk factor for local recurrence (LR) for patients undergoing resection of non-small cell lung cancer (NSCLC). This investigation was performed to confirm or refute this finding in a different patient cohort. Materials and methods: Patients were eligible if they did not have a second primary cancer within 5 years of the original diagnosis, had at least 3-month follow-up, and did not receive radiotherapy. There were 373 and 168 patients in the original (P1) and confirmatory (P2) cohorts, respectively, with 66 and 30 patients with diabetes. Results: The median follow-up was 33 months (range, 3-98 months). Diabetes was an independent risk factor for LR in a Cox model in both the P2 (p=. 0.05, hazard ratio [HR] 2.15) and P1 (p=. 0.008, HR 1.90) cohorts, separately from BMI, glucose control, and the presence of the metabolic syndrome. The rates of LR in the patients with diabetes after combining the cohorts at 2, 3, and 5 years were 23%, 33%, and 56%, respectively; these rates were 15%, 19%, and 26% in non-diabetics. In multivariate Cox regression and competing risk analysis of the combined cohorts, the HRs for LR in patients with diabetes exceeded those of more established risk factors for LR including a 1-cm increase in tumor size and lymphovascular invasion. Conclusions: Diabetes was confirmed to be an independent predictor of the risk of LR following resection of NSCLC.