Comparison of prognostic value between gastric cancer and esophageal adenocarcinoma staging system in evaluation of the patients with advanced Siewert type II adenocarcinoma of esophagogastric junction

Abstract

Objective To investigate the prognostic value between gastric cancer and esophageal adenocarcinoma staging system from International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) 8th edition in treatment of the patients with advanced Siewert type Ⅱ adenocarcinomas of esophagogastric junction (AEG) in China. Methods A total of 67 patients who were pathologically diagnosed as pT3-pT4 Siewert type Ⅱ AEG in Shanxi Provincial Cancer Hospital from November 2012 to September 2013 were enrolled. The stage distribution and survival of the patients in two staging systems were compared. The homogeneity and discriminative power of the two staging systems were compared by using likelihood ratio chi-square test and linear trend chi-square test. Log likelihood and C-index were used to evaluate the prognostic value of the two staging systems. Results The stage distribution in gastric cancer staging system of 67 patients was ⅡA (16.4%), ⅡB (14.9%), ⅢA (31.3%), ⅢB (34.3%), ⅢC (3.0%), and 5-year survival rates of ⅡA, ⅡB, ⅢA,ⅢB were 81.8%, 70.0%, 39.1% and 36.6%, respectively (χ2= 8.221, P= 0.042); the stage distribution of esophageal adenocarcinoma staging system was ⅡB (22.4%), ⅢB (40.3%) and ⅣA (37.3%), and 5-year survival rates were 80.0%, 43.7% and 40.0%, respectively (χ2= 7.671, P= 0.022). The likelihood ratio chi-square value and linear trend chi-square value of the gastric cancer classification system were more than those of esophageal adenocarcinoma staging system (7.855 vs. 6.692, 6.051 vs. 5.351), and Log likelihood estimation value of the gastric cancer classification system was less than that of esophageal adenocarcinoma classification system (241.324 vs. 242.045), and C index of the gastric cancer classification system was more than that of esophageal adenocarcinoma staging system (0.728 9 vs. 0.721 5). Conclusion UICC/AJCC 8th edition gastric cancer TNM staging system is superior to esophageal adenocarcinoma TNM staging system in predicting the prognosis of advanced Siewert type Ⅱ AEG. Key words: Stomach neoplasms; Esophageal neoplasms; Neoplasm staging; Prognosis