Lymph node metastasis of gastric cancer: comparison of Union International Contra Cancer and Japanese systems.

Background: The pN classification of gastric cancer (GC) in the Japanese system (Japanese Gastric Cancer Association; JGCA) is based on the site and distance of metastatic nodes from the primary tumour. Union International Contra Cancer (UICC) has recently proposed a classification system based on the number of nodes involved (TNM-1997). The aim of the present study is to assess which classification system is more suitable for providing a prognosis in advanced GC with lymph node metastasis.

Methods: A total of 224 patients who underwent curative gastrectomy (R0: UICC-TNM and Resection A and B: JGCA) and D2 lymphadenectomy between 1990 and 1999, and diagnosed as pT2, pT3 and pT4 GC were enrolled. Patients were followed until the end of 2002. The disease-free survival rates of patients were compared between the two-stage systems (UICC-TNM and JGCA).

Results: Using the JGCA system, there was a significant difference between the two survival curves (pN0 and pN1, P = 0.025; pN1 and pN2, P < 0.001; pN2 and pN3, P = 0.031), but the 5-year survival rate of 27 pN2 patients (32.7%) was not significantly different from that of 14 pN3 patients (34.3%, P = 0.994) using the UICC-TNM. In 47 patients with JGCA pN2, the 5-year survival rate of 18 patients with UICC-TNM pN1 (42.9%) was not significantly different from that of 18 patients with UICC-TNM pN2 (25.2%, P = 0.422) or from that of 11 patients with UICC-TNM pN3 (24.2%; P = 0.383).

Conclusions: The JGCA system is more suitable for estimating the prognosis of Japanese patients with advanced GC than the UICC-TNM.