Positron-Emission Tomography Scan-Directed Chemoradiation for Esophageal Squamous Cell Carcinoma: No Benefit for a Change in Chemotherapy in Positron-Emission Tomography Nonresponders

Introduction: Preoperative or definitive chemoradiation is an accepted treatment for locally advanced esophageal squamous cell carcinoma (ESCC). The MUNICON study showed that positron-emission tomography (PET) response following induction chemotherapy was predictive of outcomes in patients with gastroesophageal junction adenocarcinoma. We evaluated the predictive value of PET following induction chemotherapy in ESCC patients and assessed the impact of changing chemotherapy during radiation in PET nonresponders. Methods: We retrospectively reviewed all patients with locally advanced ESCC who received induction chemotherapy and chemoradiation; all patients had a PET before and after induction chemotherapy. Survival was calculated from date of repeat PET using Kaplan-Meier analysis and compared between groups using the log-rank test. Results: Of 111 patients, 70 (63%) were PET responders (defined as a 35% or more decrease in maximum standard uptake value) to induction chemotherapy. PET responders received the same chemotherapy during radiation. Of 41 PET nonresponders, 16 continued with the same chemotherapy and 25 were changed to alternative chemotherapy with radiation. Median progression-free survival (70.1 months versus 7.1 months, p < 0.01) and overall survival (84.8 months versus 17.2 months, p< 0.01) were improved for PET responders versus nonresponders. Median progression-free survival and overall survival for PET nonresponders who changed chemotherapy versus those who did not were 6.4 months versus 8.3 months (p = 0.556) and 14.1 versus 17.2 months (p = 0.81), respectively. Conclusions: PET after induction chemotherapy highly predicts for outcomes in ESCC patients who receive chemoradiation. However, our results suggest that PET nonresponders do not benefit from changing chemotherapy during radiation. Future trials should use PET nonresponse after induction chemotherapy to identify poor prognosis patients for novel therapies. (C) 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.