147P Can the clinical stage of the 8th edition of the Union for International Cancer Control TNM classification stratify prognosis of patients with Siewert type II/III cancer?

Abstract

In 2017, the 8th edition of the Union for International Cancer Control TNM classification (TNM8) was published and clinical staging system was newly defined. Recently, this clinical staging reportedly predicted the prognosis in patients with gastric cancer (GC). Different from common GC, the diagnosis and the treatment of adenocarcinoma of the esophagogastric junction (AEG) have been controversial. Moreover, its incidence also has increased in Japan. The purpose of this study was to clarify whether the prognosis of patients with Siewert type II/III tumors was appropriately stratified by the clinical staging system. Patients who were diagnosed with AEG type II/III and received gastrectomy or esophagectomy between 1986 and 2014 at Kanagawa Cancer Center were included in this study. Patients received neoadjuvant chemotherapy were excluded. A total of 196 patients were examined, 123 (63%) patients had type II tumor and 73 (37%) had type III. 41 patients were classified to clinical stage I, 40 were to stage II, 104 were to stage III, and 11 were to stage IV, respectively. The median follow-up period of the survivors was 58.3 months. The 5-year overall survival rate was 48.8 % in whole cohort and were 82.5% in stage I, 70.0% in stage II, 31.7% in stage III, and 9.1% in stage IV. The hazard ratio to stage I was 1.93 in stage II, 5.68 in stage III, and 11.8 in stage IV, which increased in a stepwise manner with the stage. The clinical staging system of TNM8 could appropriately stratify the prognosis of the patients with Siewert type II/III tumors.