Metabolic Activity on [¹⁸F]-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography and Glucose Transporter-1 Expression Might Predict Clinical Outcomes in Patients with Limited Disease Small-Cell Lung Cancer Who Receive Concurrent Chemoradiation

Background Limited disease small-cell lung cancer responds well to concurrent chemoradiation therapy (CCRT), but shows high relapse rate and short RFS. We aimed to evaluate tumor metabolic activities measured using FDG-PET as a prognostic factor and analyze its relationships with markers of tumor biologic behavior. Patients and Methods Forty-one LD-SCLC patients receiving 4 cycles of EP (etoposide 120 mg/m², days 1-3; cisplatin 60 mg/m², day 1), 2 cycles of EP (etoposide 130 mg/m², days 1-3; cisplatin 30 mg/m², day 1)-CCRT were enrolled. Maximum standardized uptake value (SUV; SUVmax) of primary tumor was revised with SUV of liver (SUVlivermax). Differences between pre-, posttreatment average SUV uptake of primary tumor, and intrathoracic lymph nodes were presented as ΔSUVliveravg. Thirty-one tumor biopsy specimens were immunostained for GLUT-1, Bcl-2, and HIF-1α. Results The median overall survival (OS), and RFS were 13.7 and 10.4 months, respectively. In multivariate analysis, pretreatment lactate dehydrogenase (LDH) and ΔSUVliveravg correlated with RFS (hazard ratio [HR], 2.8, P =.043; HR, 0.3, P =.004). Sex, LDH, objective tumor metabolic response, and SUVlivermax correlated with OS (HR, 12.1, P =.006; HR, 3.7, P =.037; HR, 10.1, P =.008; and HR, 0.2, P =.014, respectively). High GLUT-1 positivity (> 75%), and LDH level (> 400 U/L) correlated with better objective response rate (P =.012) and HIF-1α immunoreactivity score (P =.029). Conclusion ΔSUVliveravg and GLUT-1 expression might predict RFS and ORR in patients with LD-SCLC treated with definitive CCRT.