Prognostic Value of 18F-FDG PET/CT Metabolic Tumor Volume forComplete Pathologic Response and Clinical Outcomes after NeoadjuvantChemoradiation Therapy for Locally Advanced Esophageal Cancer

Abstract

Purpose/Objective: The prognostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has not yet been defined in locally advanced esophageal cancer (LAEC). This study aims to elucidate the prognostic role of PET/CT for patients treated with neoadjuvant chemoradiation (CRT) followed by esophagectomy. Materials/Methods: We retrospectively evaluated patients with LAEC treated from 2006 to 2014 with neoadjuvant CRT followed by esophagectomy. A 76 patients had pre-CRT and post CRT PET/CT scans. PET parameters maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), peak standardized uptake value (SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were recorded for both pre-CRT and post-CRT scans. The correlation of the measured parameters with pathologic complete response (pCR) and clinical outcomes was analyzed. Results: Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff values for predicting pCR. Binomial logistic regression using these optimal cutoff values was performed for pCR. A pre CRT MTV <33.1 was 4 times more likely to have a pCR (OR 4.20 95%CI 1.60 to 11.0, p=0.004). Pre CRT TLG <153 was 4.7 times more likely to have a pCR (OR 4.71 95%CI 1.78 to 12.4, p=0.002), and post CRT TLG <53.1 was 4.5 times more likely to have a pCR (OR 4.52 95%CI 1.60 to 12.7, p=0.004). On MVA, pre-CRT MTV and pre CRT TLG remained significant (p=0.006 and p=0.039, respectively). Percent change in MTV independently predicted for OS (p=0.034). By contrast, SUVmax and SUVpeak did not predict for pCR or survival. Conclusions: Pre CRT MTV and pre CRT TLG were independently predictive of pCR, and percentage change in MTV independently predicted for OS in LAEC. Further study is needed to determine if MTV and TLG values can help define which patients will most benefit from radiation dose escalation and esophagectomy