The early predictive value of a decrease of metabolic tumor volume in repeated (18)F-FDG PET/CT for recurrence of locally advanced non-small cell lung cancer with concurrent radiochemotherapy

Abstract

Purpose: The aim of this study is to investigate the value of [(18)F] fluorodeoxyglucose positron emission tomography/computed tomography ((18)F FDG PET/CT) to predict recurrence of patients with locally advanced non-small cell lung cancer (NSCLC) during the early stage of concurrent chemoradiotherapy (CCRT).

Methods: A total of 53 stage III NSCLC patients without diabetics or undergoing surgery were enrolled in the prospective study. Those patients were evaluated by FDG PET before and following 40Gy radiotherapy (RT) with a concurrent cisplatin-based heterogeneous chemotherapy regimen. Semiquantitative assessment was used to determine maximum and mean SUVs (SUVmax/SUVmean) and metabolic tumor volume (MTV) of the primary tumor. The prognostic significance of PET/CT parameters and other clinical variables was assessed using Cox regression analyses. The cutoffs of PET/CT parameters which have been determined by the previous study were used to separate the groups with Kaplan-Meier curves.

Results: Recurrence rates at 1- and 2-years were 18.9% (10/53) and 50.9% (27/53) for all patients, respectively. Cox regression analysis showed that the only prognostic factor for recurrence was a decrease of MTV. Using the cutoff of 29.7%, a decrease of MTV can separate the patients into 2 groups with Kaplan-Meier curve successfully.

Conclusion: The prospective study has reinforced the early predictive value of MTV in repeated (18)F-FDG PET/CT for recurrence in a subgroup of locally advanced NSCLC who underwent CCRT. A decrease of MTV in (18)F-FDG uptake by the primary tumor correlates with higher LRFS.

Keywords: FDG; Non-small cell lung cancer; PET; Recurrence.