Article Abstract

Metabolic volume parameters based on different thresholds with baseline 18F-FDG PET/CT as prognostic factors for survival in stage III non-small cell lung cancer

Authors: Yamin Jie, Xue Meng, Anxin Gu, Xiaorong Sun, Jinming Yu


Background: Concurrent chemo-radiotherapy is recommended as the standard treatment of stage III non-small-cell lung cancer (NSCLC) patients. However, the 5-year survival has not significantly improved during the past decade. Therefore, it is essential to find prognostic factors for specific cohort of patients. Studies have indicated that the intratumoral heterogeneity can be described by the variability in the voxel intensity of Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) within the tumor volume (TV). Hence, we presumed that certain thresholds of metabolic volume parameters such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG) might serve as prognostic factors of stage III NSCLC patients.
Methods: A total of 78 cases with stage III NSCLC were confirmed by histology or cytology and treated with concurrent chemo-radiotherapy. We computed MTV on the basis of different thresholds of standardized uptake value (SUV). TLG was calculated as the MTV multiplied by the SUVmean. The prognostic values of the PET parameters and clinical variables were assessed with Cox proportional hazards regression analysis of the overall survival (OS) and progression-free survival (PFS) for both univariate and multivariate analyses.
Results: The median follow-up time for all patients was 24.5 months (range 12–39 months). In the univariate analysis, MTV50%, MTV60%, MTV70%, TLG50%, TLG60%, ECOG and sex were significant prognostic factors of OS [P(MTV50%)=0.013, P(MTV60%)=0.002, P(MTV70%)=0.024, P(TLG50%)=0.013, P(TLG60%)=0.029, P(ECOG)=0.011, P(sex)=0.008], while MTV50%, MTV60%, MTV70%, TLG50%, TLG60%, and ECOG were significantly associated with PFS [P(MTV50%)=0.004, P(MTV60%)=0.007, P(MTV70%)=0.020, P(TLG50%)=0.006, P(TLG60%)=0.038, P(ECOG)=0.005]. In the multivariate analysis, TLG50% was significantly associated with OS (HR =0.423, P=0.023), and also significant prognostic factor of PFS [HR =0.457, P(TLG50%)=0.029]. MTV60% was significantly associated with PFS (HR =0.402, P(MTV60%)=0.042). These PET/CT parameters were separately analyzed and were adjusted for age, sex, stage, histology, ECOG, and location.
Conclusions: Volume-based PET pretreatment parameters have prognostic value in nonsurgical stage III NSCLC. A higher MTV60% predicts a worse PFS. TLG50% is negatively correlated with both OS and PFS. These would be helpful to identify proper cohorts for individualized therapeutic schedules.