Validation of the postneoadjuvant therapy pathological stage of the American Joint Committee on Cancer (AJCC) 8th Edition for predicting outcomes of esophageal squamous cell carcinoma (ESCC) patients receiving neoadjuvant chemoradiotherapy (CRT) followed by esophagectomy.

Abstract

138 Background: The AJCC 8th edition staging system introduces a new postneoadjuvant therapy staging category (ypTNM-8th) for ESCC patients receiving neoadjuvant treatment followed by esophagectomy. Whether this new staging category has better prognostic prediction than the pathological staging category of AJCC 7th edition (ypTNM-7th) needs validation. Methods: We enrolled ESCC patients receiving neoadjuvant paclitaxel/cisplatin-based CRT (RT = 40Gy) followed by esophagectomy from three phase II trials conducted in the National Taiwan University Hospital. The prognostic prediction abilities of the ypTNM-8th and the ypTNM-7th on patients’ survivals were compared using Cox regression, concordance index (C-index), R-square, and Akaike information criteria (AIC). Results: A total 135 patients (M:F = 127: 8, median age:53.0 years) were enrolled. With a median follow-up of 31.3 months, the median PFS and OS of all patients were 24.4 months (95% CI: 15.4-33.5) and 33.9 months (95% CI: 22.6-45.1), respectively. In univariate analysis, both ypTNM-8th and ypTNM-7th had statistically significant prognostic effects for PFS and OS. In multivariate analysis on OS, the ypTNM-8th demonstrated a statistically significant predicting effect (P = 0.015) while the ypTNM-7th did not (P = 0.051). Although there is no statistically different between ypTNM-8th and ypTNM-7th by R-square analysis, the ypTNM-8th had lower AIC and C-index for both PFS and OS, meaning an better efficiency of predicting survivals, than ypTNM-7th. Conclusions: The new ypTNM-8th may have better prognostic prediction for OS of locally advanced ESCC patients receiving neoadjuvant CRT than the ypTNM-7th. (Granted by 106-HCH029)