Comparison of prognostic significance of nodal staging between old (4th edition) and new (5th edition) UICC TNM classification for gastric carcinoma

The description of nodal staging for gastric cancer Has changed in the new fifth edition of the International Union Against Cancer (UICC) TNM classifi cation from the anatomic sites of metastatic lymph nodes to the number of m etastatic lymph nodes, as pN1 is metastasis in 1 to 6 lymph nodes, pN2 is i n 7 to 15 lymph nodes, and pN3 is in 16 or more lymph nodes. The purpose of this study was to investigate the prognostic significance of the new stagi ng system based on the number of metastatic lymph nodes compared to the old staging system by anatomic site. From 1987 to 1994 a total of 2108 patient s who underwent potentially curative resections with D2 or D3 lymph node di ssection and with 15 or more lymph nodes retrieved were studied retrospecti vely. Lymph node metastases were found in 1018 patients (48.3%). A mean of 37.9 lymph nodes were retrieved per patient, and a mean of 7.2 lymph nodes were invaded by tumor cells. We found that the new nodal staging based on t he number of metastatic lymph nodes closely correlated with the depth of ca ncer invasion and with the old nodal staging based on the anatomic site of the metastatic nodes, with statistical significance. The 5-gear survival ra tes after gastrectomy decreased significantly by increasing the extent of t he pN classification in both nodal staging methods. In a subgroup analysis of survivals between the old and new nodal staging, the new classification show ed more homogeneous survival at the same stage than the old one. With a multivariate analysis of prognostic factors, including the old and new no dal staging, the depth of invasion and the new nodal stage were the most si gnificant prognostic factors, followed by the old nodal stage. Our data sug gested that the new nodal staging based on the number of metastatic lymph n odes is not only a reliable and objective method For nodal classification, but it is also a significant prognostic determinant for gastric cancer that can be used in practice.