Comparison of the 7th and 8th editions of the American joint committee on cancer TNM classification for patients with stage III gastric cancer

// Jun Lu 1, 2, 3, 4 , Chao-Hui Zheng 1, 2, 3, 4 , Long-Long Cao 1, 2, 3, 4 , Ping Li 1, 2, 3, 4 , Jian-Wei Xie 1, 2, 3, 4 , Jia-Bin Wang 1, 2, 3, 4 , Jian-Xian Lin 1, 2, 3, 4 , Qi-Yue Chen 1, 2, 3, 4 , Mi Lin 1, 2, 3, 4 , Ru-Hong Tu 1, 2, 3, 4 and Chang-Ming Huang 1, 2, 3, 4 1 Department of Gastric Surgery, Fujian Medical University Union Hospital, Fuzhou, China 2 Department of General Surgery, Fujian Medical University Union Hospital, Fuzhou, China 3 Key Laboratory of Ministry of Education of Gastrointestinal Cancer, Fujian Medical University, Fuzhou, China 4 Fujian Key Laboratory of Tumor Microbiology, Fujian Medical University, Fuzhou, China Correspondence to: Chang-Ming Huang, email: hcmlr2002@163.com Keywords: gastric cancer, TNM classification, prognosis, 8th edition Received: February 02, 2017      Accepted: April 26, 2017      Published: June 06, 2017 ABSTRACT Background and Objectives: The eighth TNM edition for gastric cancer was released in 2016 and included major revisions, especially of stage III. The purpose of this study was to evaluate the prognostic value of the new AJCC TNM classification in comparison with the 7th edition for stage III gastric cancer. Methods: Clinical and histopathological data on 1,496 patients operated on for stage III GC according to the seventh edition between 2005 and 2013 were analyzed and compared using 7th and 8th classifications. The 2 systems were compared in terms of prognostic performance. Results: The stage shifted for 650 (43.45%) patients: from IIIA to IIIB (2 patient, 0.13%), from IIIB to IIIA (214 patients, 14.30%), from IIIB to IIIC (99 patients, 6.62%), and from IIIC to IIIB (335 patients, 22.39%). Cox regression multivariate analysis showed both the 8th and 7th TNM classification were independent prognostic factors. The 8th edition system had higher linear trend and likelihood ratio χ 2 scores, and smaller AIC values compared with those for the 7th edition. However, the performance of the eighth edition did not reveal significant improvement compared to the seventh edition (c-index 0.625 vs. c-index 0.616, p=0.085). Conclusion: The eighth TNM edition may not provide significantly better accuracy in predicting the prognosis of stage III GC. However, to confirm our findings, further studies are warranted.