J Cancer 2018; 9(19):3570-3576. doi:10.7150/jca.26351

Research Paper

Proposal for a New TNM Stage based on the 7th and 8th American Joint Committee on Cancer pTNM Staging Classification for Gastric Cancer

Miao-Zhen Qiu1*, Zi-Xian Wang1*, Yi-Xin Zhou2*, Da-Jun Yang3✉, Feng-Hua Wang1✉, Rui-Hua Xu1✉

1. Department of Medical Oncology, Sun Yat-Sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou 510060, China.;
2. Department of VIP, Sun Yat-Sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou 510060, China.;
3. Department of Experimental Research, Sun Yat-Sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
*Miaozhen Qiu, Zi-Xian Wang and Yi-Xin Zhou contributed equally to the manuscript.

Abstract

Background: The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for gastric cancer incorporated several new changes. We aimed to assess the comparative prognostic values of the 7th and 8th AJCC pTNM staging systems in patients with gastric cancer (GC), and accordingly, to put forward a refined staging classification.

Methods: The SEER database was queried to identify GC patients between 2004 and 2009. GC patients from Sun Yat-sen University Cancer Center (SYSUCC) were used as external validation data. The Kaplan-Meier method and Cox proportional hazards regression models were used to analyze cause-specific survival (CSS). The prognostic performance of different staging schemes was assessed using the concordance index (c-index), Akaike's information criterion (AIC), and likelihood ratio χ2 test.

Results: In the SEER cohort, stage migration occurred in 8.74% of patients. Survival analysis showed that it was better to treat T4bN0M0 + T4aN2M0 as stage IIIB and T4bN3bM0 as stage IV. Based on this, we established a new staging system which exhibited a superior c-index (0.7501) to the 7th and 8th AJCC staging systems (0.7498 and 0.7500, respectively). The new staging system also outperformed the 7th and 8th AJCC staging systems in terms of AIC and the likelihood ratio χ2 test. The predictive superiority of the new staging system remained valid in the SYSUCC database.

Conclusions: We demonstrated that some stage modifications in the 8th AJCC pathologic staging were unnecessary. Therefore we established a new staging system, which was superior to the 7th and 8th staging systems.

Keywords: Gastric Cancer, Prognosis, SEER, TNM staging classification

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/). See http://ivyspring.com/terms for full terms and conditions.
How to cite this article:
Qiu MZ, Wang ZX, Zhou YX, Yang DJ, Wang FH, Xu RH. Proposal for a New TNM Stage based on the 7th and 8th American Joint Committee on Cancer pTNM Staging Classification for Gastric Cancer. J Cancer 2018; 9(19):3570-3576. doi:10.7150/jca.26351. Available from http://www.jcancer.org/v09p3570.htm