Comparison of the 6th and 7th editions of the AJCC/UICC TNM staging system for gastric cancer focusing on the "N" parameterrelated survival: The monoinstitutional NodUs Italian study

Abstract

Background: A large number of Asian population studies examined the difference between the 6th and the 7th tumor, node, metastasis (TNM) while it is still poorly validated among Caucasian populations. This is a retrospective study aimed at investigating the efficacy of the 7th edition American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) staging system for gastric cancer focusing on the "N" parameter-related survival for prognostic assessment in gastric cancer patients of a single Western high-volume institution. Methods: From January 2002 to December 2009, the data of 274 patients with gastric cancer who underwent gastric surgery at the 8th General and Gastrointestinal Surgical Centre of the Second University of Naples were analyzed retrospectively. We collected data for patient demographics, tumor characteristics, surgical characteristics, and TNM stage. Particularly, the nodal status, with the number of dissected nodes and metastatic nodes, was reviewed from the pathology records. The same patient dataset was used to stage patients according to both the 6th and 7th edition criteria. Results: Age at surgery, tumor location, histological grade, Lauren's classification subtypes, and 6th and 7th AJCC/ UICC N categories were found to have statistically significant associations with overall survival on univariate analysis. In the 6th edition staging system, the Kaplan-Meier plot did not show significant overlapped survival curves: significant differences were found between N0 and N1, P < .001; N1 and N2, P = .04; and N2 and N3, P