A New pN Staging System Based on Both the Number and Anatomic Location of Metastatic Lymph Nodes in Gastric Cancer

Our aim was to establish a new pN staging system for gastric cancer based on the number and location of metastatic lymph nodes (MLNs) and to compare it with other systems. We retrospectively analyzed the prognostic data of 521 gastric cancer patients who underwent curative resection. Survival analyses were used to establish a pN staging system that considers both the number and location of MLNs and to compare discriminatory ability and monotonicity of gradients (linear trend chi (2) score), homogeneity ability (likelihood ratio test), and prognostic stratification ability (Akaike information criterion) between Japanese Gastric Cancer Association (JGCA) and Union for International Cancer Control (UICC) systems. Cut-point survival analysis divided pN(+) patients into two groups: Nxn(1 similar to 6) and Nxn(a parts per thousand yen7). N0, N1, N2, and N3 (the previous classifications) were replaced by N0, N1n(1 similar to 6), N2n(1 similar to 6), and N1n(a parts per thousand yen7) + N2n(a parts per thousand yen7) + N3n(16) + N3n(a parts per thousand yen7), respectively. Compared with two widely used staging s similar to ystems, the new system had the highest likelihood ratio test [106.06 (new) vs 95.09 (JGCA) vs 94.33 (UICC)] and linear trend chi (2) scores [102.30 (new) vs 89.12 (JGCA) vs 86.97(UICC)] and the lowest Akaike information criterion (AIC) score [2,283.88 (new) vs 2,285.31 (JGCA) vs 2,299.88 (UICC)]. A new pN staging system based on the number and location of MLNs is an efficient prognostic indicator of the survival of patients with gastric cancer following radical surgery.