Interim Fdg-Pet Imaging During Neoadjuvant Chemoradiotherapy For Esophageal Cancer: Correlation With Pathologic Response.

175Background: In this prospective study we evaluated whether changes in metabolic tumor parameters on interim flurodeoxyglucose positron emission tomography (FDG-PET) performed during neoadjuvant chemoradiotherapy (CRT) for esophageal cancer correlates with histopathologic tumor response. Methods: From February 2012 to February 2016, 60 patients with esophageal cancer underwent PET scans before therapy and after 30-36 Gy. Patients who underwent surgery after carboplatin/paclitaxel CRT were eligible for the current analysis. PET metrics of the primary site including maximum standardized uptake value (SUVmax), SUV mean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were extracted from the pre-treatment and interim PET based on a manual contour and SUV 2.5 threshold. Patients were called histopathologic responders if they had a complete or near complete tumor response based on the modified Ryan scheme. Relative changes in PET metrics between pre-treatment and interim PET were compared betw...