The purpose is to explore the value of the seventh edition of AJCC staging and improved AJCC staging in the evaluation of the prognosis of gastric neuroendocrine carcinoma (GNEC).
We analyzed retrospectively the clinical and pathological data of 427 GNEC patients from SEER database and 129 GNEC patients in single center. AIC and C index were used to evaluate the distinguishing capability of different TNM staging systems.
In SEER database, the 5-year survival rate stratified by AJCC staging of GENC (I, IIa, IIb, IIIa, IIIb, IV) were 68%, 61%, 46%, 22%, 21%, and 10% respectively. While in single center, the 5-year survival rate of different stages were 100%, 60%, 27%, 16%, 22%, and 0% respectively. From the survival curve analysis, there are significant crossovers between the IIIB survival curves of SEER database as well as single center and those of IIIA and IIB. In SEER database, the T staging and the age of disease diagnosis were independent factors affecting the prognosis of IIIB patients. According to the T staging, the IIIB was divided into four subgroups: T1N1,T2N1, T3N1, and T4N1. According to the principle of similar survival rate, the new AJCC staging is composed of different stages: nI(T1N0M0), n IIa (T1N1M0, T2N0M0), n IIb (T2N1M0, T3N0M0), n IIIa (T3N1M0, T4N0M0), n IIIb (T3N1M0, T4N0M0) and n IV (T1-4NxM1). The survival curve of the new AJCC staging showed less crossover per stage, obtaining a smaller AIC value (1572 vs. 1583) and a smaller c-index (0.7505 vs. 0.7421). It is discovered that through employing the data of single center as external validation, the new AJCC staging can better distinguish different TNM staging.
Dividing IIIB of the seventh edition of AJCC staging into various sub-stages has significant prognostic value and the new AJCC staging can better distinguish the stages of GNEC.
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All authors have declared no conflicts of interest.