Metabolic tumor burden as marker of outcome in advanced EGFR wild-type NSCLC patients treated with erlotinib

Abstract

ObjectivesAccurate estimation of the prognosis of advanced non-small cell lung cancer (NSCLC) patients is essential before initiation of palliative treatment; especially in the second and third-line setting. This study was conducted in order to evaluate tumor burden measured on an 2′-deoxy-2′-[18F] fluoro-D-glucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) scan as a marker of outcome in advanced epidermal growth factor receptor (EGFR) wild-type patients treated with second or third-line erlotinib. Material and methodsFifty-one patients were included from a prospectively collected cohort. An F-18-FDG-PET/CT scan was conducted prior to erlotinib treatment and tumor burden was measured in terms of metabolic tumor volume (MTV) and total lesion glycolysis (TLG). Median values of MTV and TLG were used for dichotomization of patients. Survival outcome was compared between groups. ResultsMTV and TLG could be measured in 49 patients. High values of MTV and TLG were significantly correlated with shorter PFS (p<0.001 and p=0.027, respectively) and OS (p<0.001 and p=0.002, respectively). In multivariate analyses, including both clinical and imaging data, high MTV and TLG remained strong independent markers of both shorter PFS (MTV, hazard ratio (HR)=5.44 (95% confidence interval (CI) 2.46–12.02); TLG, HR=2.17 (95% CI 1.11–4.26)) and OS (MTV, HR=4.80 (95% CI 2.08–11.06); TLG, HR=2.76 (95% CI 1.33–5.71)). ConclusionHigh MTV and TLG are independently correlated with shorter PFS and OS in advanced EGFR wild-type NSCLC patients treated with second or third-line erlotinib. Metabolic tumor burden is a highly promising clinical tool that may allow better patient selection for palliative treatment in the future.