Proposal of a new lymph node staging system for gastric cancer: study from two institutions in China.

The aim of this study was to identify the best cutoff points for lymph node classification to improve the prognostic prediction of gastric cancer in China. Patients who had undergone surgery for gastric cancer were retrospectively evaluated in two high-volume institutions from Peking University People's Hospital (PKUPH, N=503) and Affiliated Hospital of Qingdao University (AHQU, N=1,003). The prognosis of these patients was assessed according to the number of metastatic lymph nodes with an increment of one node at one time. A new lymph node classification was proposed based on the relation between prognosis and the number of metastatic lymph nodes. According to the prognostic value, the proposed node (N) stage was categorized as N0 (no regional LNs metastasis), N1 (1-3 involved regional LNs), N2 (4-6 involved regional LNs), and N3 (≥7 involved regional LNs). The hazard ratio for the proposed N classification increased steadily and reasonably compared with the 7th edition. Moreover, the Cox regression multivariate analysis showed that the proposed N classification was superior to the 7th N classification as an independent prognostic factor. The proposed N category was superior to 7th edition N category of the American Joint Committee on Cancer (AJCC) for assessing the prognosis for gastric cancer patients in China.