A novel lymph node staging system for gastric cancer including modified Union for cancer Control/American Joint Committee on cancer and Japanese Gastric Cancer Association criteria

Abstract

Background: The TNM system of the International Union for Cancer Control/American Joint Committee on Cancer (UICC/AJCC) and the Japanese Gastric Cancer Association (JGCA) systems are the most used lymph node (LN) staging systems in gastric cancer. This study estimated the influence of anatomic location-based node stations on survival and proposed a new staging method based on both the number and anatomical distribution of metastatic LNs (mLNs).

Methods: Stage I-III gastric cancer patients with radical gastrectomy were retrospectively evaluated. Overall survival (OS) was estimated in 1786 patients with UICC/AJCC stage N1-N3b disease and compared with estimates obtained using JGCA group 1-3 mLN staging.

Results: The OS of UICC/AJCC stage N1-N3b patients with group 2 JGCA mLNs was significantly worse than that of patients with only group 1 mLNs. The OS of the patients with group 2 mLNs was similar to that of patients with group 1 mLNs but in the next more advanced UICC/AJCC-N stage. The OS of patients with group 3 mLNs was worse than that of patients with any UICC/AJCC-N stage and was similar to that of N3b patients with group 2 mLNs. A new pathological node (pN) staging classification was developed that advanced the N-staging of patients with group 2 mLNs. It was a better indicator of prognosis than the eighth UICC/AJCC-N and the thirteenth JGCA group staging systems.

Conclusions: A simple, accurate pN staging system including both the number and location of mLNs had improved homogeneity, discriminatory ability, and gradient monotonicity.

Keywords: Akaike information criterion; Bayesian information criterion; Gastric cancer; Lymphatic metastasis; Neoplasm staging methods; Prognosis; Retrospective study; Stage.