Preoperative prediction of pathologic response to neoadjuvant chemoradiotherapy in patients with esophageal cancer using 18F-FDG PET/CT and DW-MRI: a prospective multicenter study

Abstract

Accurate preoperative prediction of pathologic response to neoadjuvant chemoradiotherapy (nCRT) in esophageal cancer patients could enable to forgo esophagectomy in patients with a pathologic complete response (pCR). This study aimed to evaluate the individual and combined value of 18 F-fluorodeoxyglucose positron emission tomography with integrated computed tomography ( 18 F-FDG PET/CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) during and after nCRT to predict pathologic response in esophageal cancer patients. In this multicenter prospective study, patients scheduled to receive nCRT followed by esophagectomy for esophageal cancer underwent 18 F-FDG PET/CT and DW-MRI scanning prior to start of nCRT, during nCRT, and before esophagectomy. Response to nCRT was based on histopathological evaluation of the resection specimen. Relative changes in 18 F-FDG PET/CT and DW-MRI parameters were compared between patients with pCR and non-pCR groups. Multivariable Ridge regression analyses with bootstrapped c-indices were performed to evaluate the individual and combined value of 18 F-FDG PET/CT and DW-MRI. pCR was found in 26.1% of 69 patients. Relative changes in 18 F-FDG PET/CT parameters after nCRT (ΔSUV mean,post p=0.016, and ΔTLG post p=0.024), as well as changes in DW-MRI parameters during nCRT (ΔADC during p=0.008) were significantly different between pCR and non-pCR. A c-statistic of 0.84 was obtained for a model with ΔADC during , ΔSUV mean,post and histology in classifying patients as pCR (versus 0.82 for ΔADC during and 0.79 for ΔSUV mean,post alone). Changes on 18 F-FDG PET/CT after nCRT and early changes on DW-MRI during nCRT can help identify pCR to nCRT in esophageal cancer. Moreover, 18 F-FDG PET/CT and DW-MRI might be of complementary value in the assessment of pCR. Changes on 18 F-FDG PET/CT after neoadjuvant chemoradiotherapy and early changes on DW-MRI during neoadjuvant chemoradiotherapy can help identify pathologic complete responders to neoadjuvant chemoradiotherapy in esophageal cancer. Accurate response prediction would enable physicians to individualize and adapt therapy for each individual esophageal cancer patient.