Prognostic performance of different lymph node staging systems after curative resection for Siewert type II adenocarcinoma of the esophagogastric junction

Abstract

Background: The tumor-node-metastasis (TNM) pN stage, which is based on the number of positive lymph nodes (LNs), is an important prognostic factor for patients with adenocarcinoma of the esophagogastric junction (AEG). The lymph node ratio (LNR) and log odds of metastatic lymph nodes (LODDS) staging systems are new effective indicators of prognosis. We aimed to evaluate their prognostic value in Siewert type II AEG.Methods: Patients diagnosed with Siewert type II AEG who underwent curative resection between 2004 and 2014 at Guangdong General Hospital were recruited. A Cox regression model was constructed, and prognostic performance was measured using Harrell’s concordance index (C-index) and the Akaike information criterion (AIC).Results: When LN status was modeled as a continuous variable, the LODDS system (C-index: 0.729; AIC: 940.483) outperformed the other staging systems, including the number of positive LNs (LNP) (C-index: 0.721; AIC: 946.935) and LNR (C-index: 0.725; AIC: 938.918).However,when assessed as categorical variables, the LNR staging system had a better prognostic performance (C-index: 0.752; AIC: 926.350) than the American Joint Committee on Cancer (AJCC) 8th edition TNM pN (C-index: 0.740; AIC: 934.349) and LODDS (C-index: 0.737; AIC: 939.087) staging systems. Each LNR stage is more evenly distributed than the other two staging systems. Moreover, the LODDS stage is more dependent on the TLNE.Conclusion: The LNR represented the best prognostic factor when assessed as a categorical variable and may serve as an alternative nodal staging system for AEG.