Comparing the 7th and 8th editions of the American Joint Committee on Cancer/Union for International Cancer Control TNM staging system for esophageal squamous cell carcinoma treated by definitive radiotherapy

Background We retrospectively compared the 7th and the 8th editions of The American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) TNM classification in the cohort of survival of the patients with esophageal squamous cell carcinoma (ESCC) treated by definitive radiotherapy. Methods We included in this study 403 patients with ESCC who underwent radiotherapy or chemoradiotherapy, at a total radiation dose of >= 50 Gy with curative intent from 2000 to 2016 at Kindai University Hospital, and who had no distant metastasis (excluding supraclavicular lymph node). The same patient data set was re-staged according to both the 7th and 8th editions of AJCC/UICC TNM classification. Results For the 7th edition, 5-year overall survival (OS) for stages I, II, III, and IV were 58%, 52%, 22%, and 12%, respectively, which seemed to be separable into two groups (Stages I-II and III-IV). In the 8th edition, corresponding values for stages I, II, III, and IV were 65%, 44%, 34%, and 16%, respectively, which seemed to be separated into three groups (Stage I, II-III, and IV). Conclusions The 8th edition of AJCC/UICC TNM classification is a useful predictor of OS among ESCC patients who were treated with definitive radiotherapy.