Can Clinical Response Predict Pathologic Response Following Neoadjuvant Chemoradiation for Esophageal Cancer?

Objectives: Approximately 20–40% of patients with locally advanced esophageal cancer will achieve a pathologic complete response (ypCR) following neoadjuvant chemoradiotherapy (nCRT). Predicting ypCR based on a clinical complete response (ycCR) has been a challenge. This study assessed the correlation between ycCR and ypCR, as determined from esophagectomy specimens. Methods: Patients undergoing esophagectomy following nCRT at three major institutions between 2005 and 2018 were reviewed. Restaging, including PET/CT, endoscopy with biopsy, and esophageal ultrasound (EUS), was performed to determine ycCR. Results: Six hundred sixty patients were included, with 93.3% with esophageal adenocarcinoma histology. Six hundred fifty-eight of these patients underwent PET, 304 EUS, and 584 underwent a biopsy. Following nCRT, 148 (22.4%) were found to have a ypCR. Only 12/32 (37.5%) determined to have a ycCR were found to have a ypCR, while 136/628 (21.6%) with a non-ycCR were found to have a ypCR (p 0.075). Individual modality PPV was 28% for PET, 54% for EUS, and 26% for biopsy. When PET was combined with EUS, 168 reports were concordant and the PPV of ypCR was 50%, though the number of patients was low (1/2). With all 3 re-staging modalities combined, the PPV and NPV both rose to 100%. Conclusions: Current restaging tools cannot reliably predict ypCR after nCRT. While multimodal restaging appears to be a more accurate predictor of ypCR than any testing modality alone, patients cannot reliably be advised to avoid an esophagectomy on the assumption that ycCR predicts ypCR at this time.