Is the 7th TNM edition suitable for biological predictor in early gastric cancer?

Abstract

OBJECTIVES: The previous node classification of the TNM staging system has been clear and reliable in advanced gastric cancer; however, its clinical and prognostic value in early gastric cancer (EGC) has been less definitive. In January 2010, the TNM staging system was revised. Thus, the aim of this study was to assess the suitability of the revised node staging system for the prediction of the clinical behavior of EGC.METHODS: Between January 2005 and December 2008, 1845 patients were diagnosed with EGC and underwent surgery at Severance and Gangnam Severance Hospital. Clinicopathological characteristics were analyzed with comparisons between the sixth and seventh TNM staging systems for EGC.RESULTS: According to the seventh staging system, 49 (2.7%) patients were upstaged to IIA from IB based on the sixth staging system. When comparing stage IB with IIA upstaged based on the seventh staging system, poorly differentiation, signet ring cell, diffuse, and undifferentiated histological types, perineural invasion, larger size, and younger age were more significantly associated with stage IIA than with IB. Clinicopathological factors were compared between N0/N1 and N2/N3 subgroups based on both the sixth and seventh staging systems. In mucosal cancer, larger size and lymphovascular invasion (LVI) were more significantly associated with the N2/N3 subgroup based on the sixth and seventh staging systems. However, younger age, diffuse and undifferentiated histological types were more significantly associated with the N2/N3 subgroup just based on the seventh staging system. In submucosal cancer, LVI was more significantly associated with the N2/N3 subgroup according to the sixth and seventh staging systems. However, larger size, poorly differentiation, signet ring cell, diffuse, and undifferentiated histological types, PNI, and deeper submucosal invasion were more significantly associated with the N2/N3 subgroup just based on the seventh staging system.CONCLUSIONS: Upstaging in EGC based on the revised TNM staging system reflects more aggressive biological behavior of the cancer. The new seventh AJCC TNM staging system may be informative in the prediction of the biological behavior of EGC as well as prognosis and survival.