Concurrent versus sequential neoadjuvant chemoradiation therapy for esophageal and gastroesophageal junction adenocarcinoma.

Abstract

395 Background: Neoadjuvant therapy is the standard of care for locally advanced esophageal and gastroesophageal junction (GEJ) adenocarcinoma, with most patients receiving neoadjuvant chemoradiation (CRT). CRT can be delivered concurrently or sequentially after induction chemotherapy. The purpose of this study was to evaluate pathologic complete response (pCR) and overall survival (OS) among patients who received concurrent versus sequential CRT in the National Cancer Database (NCDB). Methods: Patients who received neoadjuvant CRT and underwent curative intent esophagectomy for esophageal or GEJ adenocarcinoma from 2006-2015 were included. Patients with clinical T4 or metastatic disease were excluded. Concurrent CRT was defined as radiation treatment starting within 6 weeks of chemotherapy start. Sequential CRT was defined as radiation treatment starting greater than 6 weeks after chemotherapy start. Propensity weighting was conducted to balance patient, disease, and facility covariates between groups. Results: 12,460 patients met inclusion criteria. 11,880 (95%) patients received concurrent CRT and 580 (5%) patients received sequential CRT. Patients who received sequential CRT were significantly younger (mean age: 60.7 vs 62.2 years), had higher clinical nodal stage (N2-3: 14.7% vs 10.1%), and were more often treated at academic/research hospitals (67.1 vs 55.5) (all p≤0.001). pCR was achieved in 16.2% of patients who received sequential CRT and in 14.0% of patients who received concurrent CRT (p = 0.131). Following propensity weighting, OS was significantly improved among patients who received sequential versus concurrent CRT (HR 0.82; 95% CI 0.74-0.92; p < 0.001) with a median OS for the sequential cohort of 41.4 months versus 29.4 months for those who received concurrent CRT. Conclusions: In this retrospective study from a large national database of patients who received neoadjuvant CRT for esophageal and GEJ adenocarcinoma, sequential CRT is associated with a significant OS benefit. These results merit consideration of a well powered prospective multi-institutional randomized clinical trial to further evaluate this observed difference.