Open AccessProposal and validation of a modified staging system to improve the prognosis predictive performance of the 8th AJCC/UICC pTNM staging system for gastric adenocarcinoma: a multicenter study with external validation
Author(s) -
Fang Cheng,
Wang Wei,
Deng JingYu,
Sun Zhe,
Seeruttun Sharvesh Raj,
Wang ZhenNing,
Xu HuiMian,
Liang Han,
Zhou ZhiWei
Publication year - 2018
Publication title -
cancer communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.119
H-Index - 53
ISSN - 2523-3548
DOI - 10.1186/s40880-018-0337-5
Subject(s) - ajcc staging system , surveillance, epidemiology, and end results , medicine , staging system , cancer staging , oncology , cancer registry , survival analysis , cancer
Background The 8th edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) pathological tumor‐node‐metastasis (pTNM) staging system may have increased accuracy in predicting prognosis of gastric cancer due to its important modifications from previous editions. However, the homogeneity in prognosis within each subgroup classified according to the 8th edition may still exist. This study aimed to compare and analyze the prognosis prediction abilities of the 8th and 7th editions of AJCC/UICC pTNM staging system for gastric cancer and propose a modified pTNM staging system with external validation. Methods In total, clinical data of 7911 patients from three high‐capacity institutions in China and 10,208 cases from the Surveillance, Epidemiology, and End Results (SEER) Program Registry were analyzed. The homogeneity, discriminatory ability, and monotonicity of the gradient assessments of the 8th and 7th editions of AJCC/UICC pTNM staging system were compared using log‐rank χ 2 , linear‐trend χ 2 , likelihood‐ratio χ 2 statistics and Akaike information criterion (AIC) calculations, on which a modified pTNM classification with external validation using the SEER database was proposed. Results Considerable stage migration, mainly for stage III, between the 8th and 7th editions was observed in both cohorts. The survival rates of subgroups of patients within stage IIIA, IIIB, or IIIC classified according to both editions were significantly different, demonstrating poor homogeneity for patient stratification. A modified pTNM staging system using data from the Chinese cohort was then formulated and demonstrated an improved homogeneity in these abovementioned subgroups. This staging system was further validated using data from the SEER cohort, and similar promising results were obtained. Compared with the 8th and 7th editions, the modified pTNM staging system displayed the highest log‐rank χ 2 , linear‐trend χ 2 , likelihood‐ratio χ 2 , and lowest AIC values, indicating its superior discriminatory ability, monotonicity, homogeneity and prognosis prediction ability in both populations. Conclusions The 8th edition of AJCC/UICC pTNM staging system is superior to the 7th edition, but still results in homogeneity in prognosis prediction. Our modified pTNM staging system demonstrated the optimal stratification and prognosis prediction ability in two large cohorts of different gastric cancer populations.