Evaluation of the seventh TNM classification system in patients with esophageal cancer receiving chemoradiotherapy.

Abstract

83 Background: The new 7th edition of the TNM classification system is based on pathologic data of esophageal cancer underwent surgery alone. No report is available on the prognostic evaluation of the new staging system in patients treated with chemoradiotherapy (CRT). The objective of this study was to evaluate the prognostic impact of the 7th edition of the TNM staging system in esophageal cancer patients treated with CRT. Methods: A retrospective review was performed of 301 consecutive patients who met the following inclusion criteria: (1) squamous cell carcinoma of thoracic esophagus; (2) total radiation dose ≥ 50 Gy; (3) concomitant chemotherapy consisting of 5-fluolouracil and platinum; (4) no previous thoracic radiotherapy or surgery. We compared the prognostic impact of the 6th and 7th editions of the TNM staging systems. Also, we compared the prognostic impact of stage group and prognostic group, which was newly defined in the 7th edition. Survival analysis was performed by using log-rank and Cox regression testing. Results: Patients with stage I/II/III/IV were 52/42/54/153 and 57/46/128/70 according to 6th and 7th edition, respectively. Eighty-four patients were shifted to a lower stage in 7th edition compared with 6th edition, and most of these were from stage IV to III (n = 74). There were significant differences among stages I to III (p < 0.01, respectively) according to each edition. However, 7th edition poorly distinguishes between stages III and IV (p = 0.43). The survival curve of stage IV (lymph) almost completely overlapped with stage III (p = 0.69), although there were significant differences between stages IV (lymph) and IV (organ) (p = 0.04). Among the factors included in prognostic group in 7th edition, the histological grade and cancer site had no significant influence on patient survival, and T factor was only independent prognostic factors in multivariate analysis (p < 0.01). Conclusions: Our study suggested several pitfalls in 7th TNM classification as prognostic factor in patients who received CRT. No significant financial relationships to disclose.