Significance of 18F-FDG PET parameters according to histologic subtype in the treatment outcome of stage III non–small-cell lung cancer undergoing definitive concurrent chemoradiotherapy

Abstract

We examined the prognostic role of positron emission tomography-computed tomography (PET-CT) parameters in patients with stage III non small-cell lung cancer treated with definitive chemoradiotherapy according to histology. With lower PET-CT parameters, adenocarcinoma showed significantly worse distant metastasis-free survival. Our results validate and highlight the need for consideration of histologic subtypes as well as PET-CT parameters when predicting clinical outcomes. Purpose: We analyzed positron emission tomography-computed tomography (PET-CT) in patients with stage III non-smallcell lung cancer (NSCLC) undergoing concurrent chemoradiotherapy (CRT) to examine the prognostic value of PET-CT parameters according to histologic subtypes (squamous cell carcinoma [SqCC] and adenocarcinoma [ADC]). Methods: A total of 130 patients with stage III NSCLC who underwent definitive CRT were identified. We obtained PET-CT parameters such as maximum (SUVmax) and mean (SUVmean) standardized uptake value, total lesion glycolysis (TLG), metabolic tumor volume (MTV), and coefficient of variation (CV). Each parameter was bifurcated based on the optimal cutoff, and propensity score matching was performed between the SqCC and ADC groups. Results: There were 108 patients with SqCC or ADC, and 44 patients each were allocated to the SqCC and ADC groups via propensity score matching. SUVmax, SUVmean, TLG, and MTV values were significantly higher in SqCC than in ADC (P = .004, P = .006, P = .003, and P = .03, respectively). In the SqCC group, PET-CT parameters were not associated with survival outcomes. However, in the ADC group, SUVmax and SUVmean, were related to locoregional progression-free survival (P = .008 and P = .017, respectively), and TLG and MTV were related to overall survival (P = .044 and P < .001, respectively). In addition, patients with ADC showed more frequent distant metastasis (P = .011) and worse distant metastasis-free survival compared with patients with SqCC (P = .009). Conclusions: PET-CT provided different prognostic implications between SqCC and ADC in patients with locally advanced NSCLC receiving radical CRT. This suggests that it is necessary to consider the histologic subtype and PET-CT parameters concurrently when predicting survival outcomes. (C) 2018 Elsevier Inc. All rights reserved.