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

BACKGROUND. The lymph node (N) classification in the International Union Ag ainst 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 me tastasis. Both classification systems were compared for prognostic signific ance. 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 classif ied as pN1 and 711 patients as pN2. When reclassified, 587 patients remaine d pN1, 54 patients became pN2, and 6 patients became pN3. Of the 711 pN2 pa tients, 333 became pN1, 267 remained pN2, and 111 patients became pN3. Both lymph node classification methods defined groups with widely differing pro gnoses. The prognoses of patients classified as new pN2 were more homogeneo us than those of the group classified as old pN2. Survival of new pT4/pN1 p atients was significantly better than that of other subgroups in Stage IV. Nine potential prognostic factors, including lymph node metastasis, were st udied 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 we re 1.51 (1.29-78) for pN1, 3.11 (2.56-3.78) for pN2, and 3.88 (2.98-5.05) f or 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) 2 000 American Cancer Society.