Background: Diabetes is related with increased cancer mortality across multiple cancer types. Its role in lung cancer mortality is still unclear. We aim to determine the prognostic value of fasting plasma glucose (FPG) and diabetes mellitus in patients with locally advanced non-small cell lung cancer (NSCLC) treated with concurrent chemoradiotherapy.
Methods: One-hundred seventy patients with stage III NSCLC received definitive concurrent chemoradiotherapy from 2010 to 2014. Clinico-pathological data and clinical outcome was retrospectively registered. Fifty-six patients (33%), met criteria for type 2 diabetes mellitus (T2DM) at baseline. The prognostic value of FPG and other clinical variables was assessed. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method and Cox proportional models and log-rank test were used.
Results: With a median follow-up of 36 months, median PFS was 8.0 months and median OS was 15.0 months in patients with FPG ≥7 mmol/L compared to 20 months (HR 1.13; 95% CI 1.07-1.19, p < 0.001) and 31 months (HR 1.09; 95% CI 1.04-1.15; p < 0.001) respectively, for patients with FPG < 7 mmol/L. In the multivariate analysis of the entire cohort adjusted by platinum compound and comorbidities, high levels of FPG as a continuous variable (HR 1.14; 95% CI 1.07-1.21; p < 0.001), the presence of comorbidity (HR 1.72; 95% CI 1.12-2.63; p = 0.012), and treatment with carboplatin (HR 1.95; 95% CI 1.26-2.99; p = 0.002) were independent predictors for shorter OS. In additional multivariate models considering non-diabetic patients as a reference group, diabetic patients with poor metabolic control (HbA1c > 8.5%) (HR 4.53; 95% CI 2.21-9.30; p < 0.001) and those receiving insulin (HR 3.22; 95% CI 1.90-5.46 p < 0.001) had significantly independent worse OS.
Conclusion: Baseline FPG level is an independent predictor of survival in our cohort of patients with locally advanced NSCLC treated with concurrent chemoradiotherapy. Studies in larger cohorts of patients are warranted to confirm this relevant association.
Keywords: Comorbidities; Concurrent chemoradiotherapy; Hyperglycemia; Locally advanced unresectable non-small cell lung cancer; Type 2 diabetes mellitus.