PET-Uptake Reduction into Lymph Nodes After Neoadjuvant Therapy is Highly Predictive of Prognosis for Patients Who have Thoracic Esophageal Squamous Cell Carcinoma Treated with Chemoradiotherapy Plus Esophagectomy.

Background: Patients with F-fluorodeoxyglucose-positron emission tomography (FDG-PET)-positive lymph nodes before treatment have a poor prognosis after esophagectomy. This study investigated whether FDG uptake into lymph nodes on FDG-PET (PET-N) during the pre- or posttreatment stage is more predictive of survival for thoracic esophageal squamous cell carcinoma (TESCC) patients who received neoadjuvant chemoradiotherapy (NACRT) followed by esophagectomy.

Methods: Of 129 TESCC patients with clinical lymphatic metastasis who underwent curative-intent esophagectomy after NACRT between 2010 and 2018, 97 who received PET before and after NACRT were enrolled in the study. The study defined lymph nodes with a maximum standardized uptake value (SUV) greater than 2.5 on FDG-PET before NACRT as cPET-N(+) and after NACRT as CRT-cPET-N(+). Both the cPET-N(+) and CRT-cPET-N(-) patients were defined as PET-N responders. Survival was analyzed using the Kaplan-Meier method and Cox proportional hazard models.

Results: No significant difference in survival was detected between the cPET-N(+) and cPET-N(-) patients. However, the CRT-cPET-N(-) patients had significantly better 5-year overall survival (OS) and disease-specific survival (DSS) than the CRT-cPET-N (+) patients. The PET-N responders had significantly better 5-year OS and DSS than the PET-N non-responders, and PET-N response was an independent prognostic factor for 5-year DSS.

Conclusion: The PET-N response is a highly predictive prognostic marker for TESCC patients who undergo NACRT followed by esophagectomy. The PET-N response may help clinicians to establish a strategy for perioperative treatments that improves survival for patients with lymph node metastasis in TESCC.