The aim of this study was to establish an appropriate N staging system for early gastric cancer (EGC).
Data from 24,223 patients who underwent radical gastrectomy between 1988 and 2011 were retrieved from the National Cancer Institute’s Surveillance, Epidemiology, and End Result (SEER) database. The optimal cutoff value for the number of LNs was determined by the X-tile program. The overall survival (OS) based on eighth edition and new TNM staging systems were compared, and the analysis was repeated in an external validation set.
In the same T category, the OS rates were significantly different in each N category for advanced gastric cancer (AGC). However, no significant differences were observed in OS between N1 and N2 cancers or between N3a and N3b cancers in cases of EGC. The X-tile program identified that the difference in survival was most significant when 6 metastatic LNs were present. The new staging system for EGC consisted of T1N0, T1N1’ (1-6 metastatic LNs) and T1N2’ (≥7 metastatic LNs). Compared with the eighth edition of the TNM staging system, the OS of patients in the T1N1’ stage was similar to that of patients with stage IIA disease, whereas the OS of patients in the T1N2’ stages was similar to that of patients with stage IIB disease (P
The N category of the eighth edition of the AJCC TNM classification exhibits variation in the survival of patients with AGC. However, this classification remains associated with some stage migration in EGC and the proposed N category permits better prognostic prediction.
Clinical trial identification
Legal entity responsible for the study
All authors have declared no conflicts of interest.