Validation of the new AJCC TNM staging system for gastric cancer in a large cohort of patients (n=2,155): Focus on the T category

Abstract
Background: The prognostic value of T subclassification in patients with gastric carcinoma has been just implemented in the new MCC TNM staging system, which has reclassified T2a and T2b into T2 and T3 tumors, respectively. The aim of the present study was to validate the prognostic significance of the new T categorization within the frame of the latest TNM staging system.

Methods: We retrospectively reviewed the records of 686 T2/T3 patients among 2155 subjects who underwent radical resection for gastric carcinoma at six Italian centers from 1988 through 2006.

Results: Upon multivariate analysis, the new T categories, extent of lymph node dissection (D) and patient's age were retained by the survival model as independent prognostic factors. In particular, the death risk for patients with T3 tumors was higher than that of patients with T2 tumors (HR: 1.42, P = 0.005).

Among the 686 patients previously classified as having T2 tumors, patients with T2 and T3 disease were 270 (39.4%) and 416(60.6%), respectively. After a median follow-up of 55 months, the 5-year overall survival rates were 67.3% and 52.3% for patients with T2 and T3 tumors, respectively (P < 0.001). The survival advantage for the T2 as compared to T3 category was maintained even when NO and N+ patients were separately considered (P = 0.0154 and P < 0.001, respectively).

Conclusions: Our data confirm the prognostic difference between the newly proposed T2 and T3 categories, which should be implemented in the routine clinical practice to improve risk stratification of patients with gastric cancer. (C) 2011 Elsevier Ltd. All rights reserved.