Application of the 8th AJCC TNM Staging System in Patients with Esophageal Squamous Cell Carcinoma.

Background. The eighth edition of the American Joint Committee on Cancer Tumor-Node-Metastasis staging system separates classifications for the clinical (c), pathologic (p), and postneoadjuvant pathologic (yp) stages. We aimed to evaluate its application in patients with esophageal squamous cell carcinoma (ESCC). Methods. Patient data were obtained from the Taiwan Cancer Registry database. Patients who underwent esophagectomy for c stage I to III ESCC were included for survival analysis. Results. Data of 3,399, 1,805, and 1,594 patients were included for c, p, and yp staging, respectively. The 3-year overall survival (OS) rates for c stage I, II, and III were 67.4%, 46.7%, and 38.4%, respectively. The 3-year OS rates for p stage I, II, III, and IV were 70.7%, 49.8%, 30.8%, and 10.6%, respectively. The 3-year OS rates for yp stage I, II, III, and IV were 59.4%, 37.8%, 27.6%, and 3.7%, respectively. Survival curve analysis demonstrated a robust discriminatory capability and monotonicity of gradients of the new system. However, yp stage I was observed in a heterogeneous group of patients with substantial survival differences. Meanwhile, patients in the ypT0 N0 stage had a 5-year OS rate of 52.1%, which was equivalent to that of patients with p stage I (54.5%). The 5-year OS rate of patients in the ypTis-2N0 was 39.1%, which was equivalent to that of patients in p stage II (40.1%). Conclusions. The present study serves as an external validation of the newly released staging system in the prognostication of patients with ESCC and suggests subgrouping of the yp stage I into ypT0 N0 and non-ypT0 N0 in the future. (C) 2018 by The Society of Thoracic Surgeons