Should All Stage N3b Patients with Advanced Gastric Cancer Be Considered Equivalent? A 30-Year Single Center Study.

Purpose: To investigate the survival of stage N3b patients with advanced gastric cancer (AGC) after radical surgery and to evaluate the TNM staging of subgroups of stage N3b patients.

Methods: We reviewed the data of 222 stage N3b patients with AGC who underwent D2/D3 radical surgery. Depending on the number of metastatic lymph nodes (MLNs), we divided N3b patients into several groups and compared the survival differences among them. We found that survival of patients with 16-20 MLNs was better than that of patients with ≥ 21 MLNs. Therefore, we divided the N3b patients into two subgroups and defined patients with 16-21 MLNs as N3b1 and patients with ≥ 21 MLNs as N3b2. Then, we compared survival differences between the two groups and their subgroups. Patients who underwent palliative surgery served as the reference group. In addition, we selected stage IIIB, IIIC, and IV patients from the same database to properly re-classify the N3b subgroups in the TNM staging system.

Results: Survival differed significantly between the new N3b1and N3b2 groups and between the new N3b1 group and the palliative group. However, the survival of the new N3b2 group was similar to that of the palliative group. Comparisons of survival according to T staging revealed similarities between the following groups: (1) stages T2-3N3b1 and IIIB, (2) stages T4N3b1 and IIIC, and (3) stages T2-4N3b2 and IV.

Conclusions: All stage N3b patients with AGC should not be considered equivalent. A significant difference in survival was observed between stage N3b1 and N3b2 patients after radical surgery, while the survival of stage N3b2 patients was similar to that of patients who undergo palliative surgery. We recommend re-classifying stage T2-3N3b1 as TNM stage IIIB, stage T4N3b1 as stage IIIC, and T2-4N3b2 as stage IV.