Locally advanced esophageal cancer: Evaluation of prognosis by assessment of the “yp” stage based on the neoadjuvant regimen received.

Abstract

356 Background: Neoadjuvant treatment in the form of chemoradiotherapy (nCRT) or chemotherapy (nCT) for resectable oesophageal cancer is the standard of care and improves R0 resection rates and overall survival (OS). The recently reported Neo-AEGIS study demonstrated ongoing equipoise between neoadjuvant chemoradiotherapy and peri-operative chemotherapy for oesophageal adenocarcinoma. There is limited data evaluating the prognostic outcomes by evaluation of the pathological stage after resection (yp stage) based on the neoadjuvant regimen received. The aim of this study was to look at the survival outcomes of patients with oesophageal cancer who received neoadjuvant therapy and to analyze the prognostic significance of pathological stage at surgery (“yp” stage) compared to the clinical stage based on the neoadjuvant therapy received. Methods: This was a single- centre, retrospective study over a fifteen-year period between 2005 and 2019. Consecutive patients with oesophageal and GOJ cancers that underwent resection post neoadjuvant treatment were included. The unit policy was to treat adenocarcinoma of the oesophagus and GOJ with perioperative chemotherapy until 2015 after which it was switched to neoadjuvant chemoradiotherapy in the form of the CROSS protocol. Results: Neoadjuvant treatment with either neoadjuvant chemoradiotherapy (nCRT) or neoadjuvant chemotherapy (nCT) prior to surgical resection was undertaken in 137 patients with resectable oesophageal and GOJ cancers between the years 2005 and 2019. The median age was 65 and 79% of the cohort was male. The majority of tumours were located in the lower oesophagus or GOJ and 96 patients in the cohort were clinical stage 3. 126 patients had adenocarcinoma and 11 patients had squamous cell carcinoma. 72 patients received nCT, and 65 patients received the nCRT. The “yp” stage showed 26 patients achieved a complete pathological response (CPR) and 47 patients were down-staged. The clinical stage was not a predictor of overall survival (p = 0.65). On the other hand, the “yp” stage was a significant predictor of survival (p < 1×10-8). In patients who received nCRT, 18 achieved a complete pathological response compared to 8 patients who had received nCT. Patients who received nCRT showed improved survival compared to patients who received nCT (p = 0.043). Patients who achieved a CPR with neoadjuvant chemotherapy had an OS of 100% compared to OS of 80% in patients who received nCRT (p = NS). Neoadjuvant chemoradiotherapy was associated with less loco-regional recurrences and distant recurrences compared to neoadjuvant chemotherapy. Conclusions: The “yp” stages, as well as down-staging with neoadjuvant therapy are strong predictors of survival. A greater proportion of patients achieved down-staging and CPR following neoadjuvant chemoradiotherapy compared to neoadjuvant chemotherapy.