Comparison of the 8th UICC staging system for esophageal and gastric cancers in Siewert type II junctional adenocarcinomas

Abstract

BackgroundThe aim of this study is to evaluate whether adenocarcinomas of the esophagogastric junction (AEG) are better staged as cancers of the esophagus (TNM-EC) or stomach (TNM-GC) according to the 8th edition of the UICC classification. MethodsA single-center cohort of 246 patients operated on for AEG type II was staged according to the 8th edition of the UICC classification for esophageal and stomach cancer. Kaplan-Meier and univariate Cox regression analyses were performed to investigate the impact on survival. ResultsFor AEG type II TNM-EC classified most of the patients (n = 126; 51.2%) to UICC stage IIIC and IVA while TNM-GC more evenly distributed the patients over the stages. Hazard ratios increased in between all stages in a stepwise manner except between stage IA and IIA for TNM-EC and between stage IIB and IIIA for TNM-GC. Survival curves for TNM-GC demonstrated significant differences between all four major UICC stages, while in TNM-EC no significant difference between stage I and II was found. When comparing the area under the curves of both staging systems a marginal superiority for TNM-EC was found. ConclusionNeither the esophageal nor the stomach staging system is flawless in predicting survival in AEG type II. A marginal superiority of the TNM-EC was found in discriminating survival rates after three and five years. However, the advantage of the TNM-GC lies in the division of the N3 category into N3a and N3b. We therefor suggest a similar division in future TNM-EC classifications to improve its prognostic value.