Prognostic significance of lymph node station 7 for patients with gastric cancers underwent radical surgery

To investigate the validity of gastric cancers with nodes metastasis at Level II stations limited to No. 7 being classified as level-based n1 stage disease and the impact of this revision on lymph node staging.Clinicopathologic features and prognosis of 1,606 node positive gastric cancers were retrospectively reviewed. Four patient groups were classified according to the status of node involvement: Group A, 734 patients with node metastasis at Level I stations; Group B, 317 patients with nodes metastasis at Level II stations limited to No. 7; Group C, 501 patients with nodes metastasis at Level II stations besides No. 7; and Group D, 54 patients with nodes metastasis at Level III stations.Although the extent of node metastasis for patients in Group B was more severe than that for patients in Group A, clinicopathologic features (especially pT stage) were not significantly different. Although overall survival for patients in Group B was significantly worse than that for patients in Group A, no significant differences in prognosis could be observed when stratified by pN or rN category. A revised level-based n category was established by considering cancers in Group B as level-based n1 stage disease. Multivariate analysis confirmed rN category and the revised level-based n category independently predicted patients' survival. A novel N category was established by combining rN category and the revised level-based n category. Further analysis revealed the novel N category had better homogeneity, discriminatory ability, and monotonicity of gradients than the other node categories, indicating the novel N system might be the most valuable node staging system for prognostic assessment.It might be more suitable for cancers in Group B being classified as level-based n1 stage disease. And we recommend the anatomical location of metastatic lymph nodes also being considered in the categorization of lymph node metastasis.