Can Clinical Stage in the 8th Edition of the Union for International Cancer Control TNM Classification Stratify the Prognosis of Patients Undergoing Curative Surgery for Siewert Type II/III Adenocarcinoma of the Esophagogastric Junction?

Background/Aim: Clinical staging in the eighth edition of the Union for International Cancer Control TNM classification (TNM8) is reported to predict the prognosis of patients with gastric cancer. However, there have been no reports on using the TNM8 for prognostic stratification of patients with adenocarcinoma of the esophagogastric junction (AEG). This study aimed to investigate whether it was possible to stratify the prognosis of patients who underwent curative surgery for Siewert type II/III AEG according to the TNM8 clinical stage (cStage). Patients and Methods: This study included patients with Siewert type II/III AEG who underwent curative surgery between 2000 and 2019 at Kanagawa Cancer Center. Those who received neoadjuvant chemotherapy were excluded. We investigated the survival of patients with AEG of each TNM8 cStage. Results: This study included 138 patients, among whom 102 (74%) had Siewert type II and 36 (26%) had Siewert type III AEG. A total of 50, 38, 43, and seven patients were classified with cStage I, II, III, and IV, respectively. The median duration of follow-up of the survivors was 54.7 months. The 5-year overall survival rate of the entire cohort was 65.8%, whereas for patients with cStage I, II, III and IV was 81.6%, 69.0%, 54.3% and 14.3%, respectively. The hazard ratio with reference to cStage I was 1.83, 3.07, and 8.13 for cStage I, III, and IV, respectively, increasing in a stepwise manner. Conclusion: TNM8 Clinical staging is able to stratify the prognosis of patients with Siewert type II/III AEG.