Perigastric lymph node metastases in gastric cancer: comparison of different staging systems

BACKGROUND: Perigastric lymph node metastases in gastric cancer are classified differently by different staging systems: the distance of positive nodes from the primary tumor is considered by the 1987 International Union Against Cancer (UICC)-TNM system, but not by the Japanese staging system (of the Japanese Research Society for Gastric Cancer [JRSGC]); the new UICC-TNM system of 1997 is based on the number of involved nodes without differentiating perigastric from regional nodes. The aim of the present study was to assess which classification was more useful to predict prognosis in gastric cancer patients with metastases to the perigastric nodes.METHODS: The results for 107 patients with lymph node metastases to the first and second tiers who underwent curative gastrectomy for gastric cancer from March 1988 to October 1997 were analyzed. In particular, we compared the clinical characteristics and the survival probabilities of: (1) patients with metastases to perigastric nodes located within 3 cm from the primary tumor, classified as N1; (2) patients with metastases to perigastric nodes located 3 cm beyond the primary tumor (N2 in the UICC-TNM and N1 in the Japanese classification), classified by us as N1-N2; and (3) patients with metastases to the second tier (classified by us as N2). We also assessed the number of positive nodes dividing the patients into groups according to the 1997 UICC TNM system.RESULTS: On multivariate survival analysis, the mortality risks in the N1 and N1-N2 patients were comparable (relative risk [RR], N1-N2 versus N1, 1.32; 95% confidence interval [CI], 0.53-3.51) and were half the mortality risk in N2 patients (RR, N2 versus N1, 2.52; 95% CI, 1.33-4.79). The N1 and N1-N2 categories, while presenting markedly different distributions in the number of metastatic nodes (patients with more than seven metastatic nodes constituted less than 20% of the N1 group and more than 60% of the N1-N2 group), showed similar prognostic significance.CONCLUSION: In the present series, the distance of perigastric nodes from the primary tumor did not seem to exert a significant effect on prognosis, and the use of a combined classification based on anatomical location (JRSGC) and number of node metastases (UICC-TNM 1997) could be more useful than either system alone for prognostic purposes.