Evaluation of the New International Union Against Cancer TNM staging for gastric carcinoma

BACKGROUND. The lymph node (N) classification in the International Union Against Cancer (UICC) TNM staging system for gastric adenocarcinoma has been revised. The new classification is based on the number of positive regional lymph nodes instead of the anatomic location of the regional lymph node metastasis. Both classification systems were compared for prognostic significance. METHODS. A total of 4362 gastric carcinoma patients who underwent resection between 1969 and 1990 were analyzed. RESULTS. Thirteen percent of patients could not be staged according to the new system. Based on the previous classification, 647 patients were classified as pN1 and 711 patients as pN2. When reclassified, 587 patients remained pN1, 54 patients became pN2, and 6 patients became pN3. Of the 711 pN2 patients, 333 became pN1, 267 remained pN2, and 111 patients became pN3. Both lymph node classification methods defined groups with widely differing prognoses. The prognoses of patients classified as new pN2 were more homogeneous than those of the group classified as old pN2. Survival of new pT4/pN1 patients was significantly better than that of other subgroups in Stage IV. Nine potential prognostic factors, including lymph node metastasis, were studied in multivariate analysis. The hazard ratios were 1.38 (1.16-1.64) for pN1 and 2.55 (2.16-3.01) for pN2, based on the old classification. They were 1.51 (1.29-78) for pN1, 3.11 (2.56-3.78) for pN2, and 3.88 (2.98-5.05) for pN3, based on the new classification. CONCLUSIONS. The new N classification is superior as a prognostic factor to the old N classification, although there is inadequacy in stage grouping. [See editorial on pages 1763-5, this issue.] Cancer 2000;88:1796-800. (C) 2000 American Cancer Society.