Measurement of tumor volume by PET to evaluate prognosis in patients with advanced non-small cell lung cancer treated by non-surgical therapy

Abstract

Patients with advanced non-small cell lung cancer (NSCLC) seem to have disparity in prognosis. Accurate prediction of prognosis could be useful in the future to predict individual risk and to develop more aggressive or alternative treatment strategies. To evaluate the prognostic value of metabolic tumor volume (MTV) measured by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in patients with NSCLC. We retrospectively reviewed 120 patients with pathologically proven NSCLC (61 squamous cell carcinomas and 59 adenocarcinomas) who underwent pretreatment 18F-FDG PET. MTV and maximum standardized uptake value (SUVmax) for the primary tumors were measured by 18F-FDG PET. Pretreatment variables (age, sex, American Joint Committee on Cancer [AJCC] stage, histological type, SUVmax, and MTV) were analyzed to identify their correlation with two-year survival. To further evaluate and compare the predictive value of PET parameters, MTV, and SUVmax, time-dependent receiver-operating characteristic curve (ROC) analysis was used. In the univariate analysis, AJCC stage, histological type, MTV, and SUVmax of primary tumor were significant predictors of survival. On multivariate analysis, independent prognostic factors associated with decreased two-year survival were AJCC stage (hazard ratio [HR] 2.236, P = 0.003), histological type (HR 2.038, P = 0. 004), and MTV (HR 1.016, P = 0.001). SUVmax was not a significant factor (HR 0.96, P = 0.490). On time-dependent ROC analysis, MTV showed good predictive performance for two-year survival consistently better than SUVmax. MTV, a volumetric parameter of 18F-FDG PET, is an important independent prognostic factor for survival and a better predictor of survival than SUVmax for the primary tumor in patients with advanced NSCLC.