Value of metabolic tumor volume on repeated 18F-FDG PET/CT for early prediction of survival in locally advanced non-small cell lung cancer treated with concurrent chemoradiotherapy.

Abstract

The aim of this study was to investigate the value of standardized uptake values (SUVs) and metabolic tumor volume (MTV) in (18)F-FDG PET/CT to predict the survival of patients with locally advanced non-small cell lung cancer during the early stage of concurrent chemoradiotherapy. A total of 53 patients were included in the prospective study. All patients were evaluated by (18)F-FDG PET before and after 40 Gy of radiotherapy with a concurrent cisplatin-based chemotherapy regimen. Semiquantitative assessment was used to determine the maximum and mean SUVs (SUV(max) and SUV(mean), respectively) and MTV of the primary tumor. The cutoffs for changes in SUV(max), SUV(mean), and MTV (37.2%, 41.7%, and 29.7%, respectively) determined in a previous study were used with Kaplan-Meier curves to separate the groups. The prognostic significance of PET/CT parameters and other clinical variables was assessed using Cox regression analysis. Overall survival (OS) at 1 and 2 y was 83.0% (46/53) and 52.8% (28/53), respectively. Survival curves for SUV(mean) and MTV were significantly different using the cutoffs. However, Cox regression analysis showed that the only prognostic factor for OS was a decrease in MTV. The use of repeated (18)F-FDG PET to assess survival early during concurrent chemoradiotherapy is possible in patients with locally advanced non-small cell lung cancer. A decrease in MTV according to (18)F-FDG uptake by the primary tumor correlates with higher long-term OS.