Published online Jan 26, 2019. doi: 10.12998/wjcc.v7.i2.145
Peer-review started: August 14, 2018
First decision: October 5, 2018
Revised: November 13, 2018
Accepted: November 23, 2018
Article in press: November 24, 2018
Published online: January 26, 2019
To establish an appropriate N classification system for early gastric cancer (EGC).
Data from 10714 patients who underwent radical gastrectomy between 1988 and 2011 were retrieved from the National Cancer Institute’s Surveillance, Epidemiology, and End Result database. The overall survival (OS) based on the eighth edition and new tumor lymph node metastasis (TNM) staging systems were compared, and the analysis was repeated in an external validation set from the Fujian Medical University Union Hospital database.
There were no significant differences in OS between N1 and N2 cancers or between N3a and N3b cancers in cases of EGC. The X-tile program identified that the new staging system for EGC consisted of T1N0, T1N1’ [1-6 metastatic lymph nodes (LNs)], and T1N2’ ( ≥ 7 metastatic LNs). Compared with the eighth edition of the TNM staging system, the OS of patients in T1N1’ stage was similar to that of patients with stage IIA disease, whereas the OS of patients in T1N2’ stage was similar to that of patients with stage IIB disease. The new TNM staging system exhibited a slightly lower Akaike Information Criterion value and higher χ2 and c-statistic compared with the eighth edition of the TNM classification system. Similar results were found in the external validation dataset from the external validation set.
We have developed an optional new TNM staging system with a better predictive ability that can be used to accurately predict the 5-year OS of patients with EGC.
Core tip: The overall survival (OS) was not significantly different between N1 and N2 cancers or between N3a and N3b cancers in cases of early gastric cancer (EGC). We identified a new metastatic lymph node classification for EGC which consisted of T1N1’ (1-6 metastatic LNs) and T1N2’ ( ≥ 7 metastatic LNs). The OS of patients in T1N1’ stage was similar to that of the 8th edition American Joint Committee on Cancer stage IIA disease, while the OS of patients in T1N2’ stage was not significantly different from that of patients with stage IIB disease. The new TNM staging system has a better predictive ability of OS for EGC.