Influence of Primary Tumor Resection on Survival of Patients With Metastatic Siewert Type II Adenocarcinoma of the Esophagogastric Junction: A Population-Based, Propensity-Matched Analysis

Objective: It remains unclear whether primary tumor resection improves survival in patients with metastatic Siewert type II adenocarcinoma of the esophagogastric junction (AEG). Therefore, our study attempted to investigate the prognostic value of primary tumor resection on metastatic AEG.Methods: In total, 4200 patients diagnosed with metastatic AEG were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2015. Patients were categorized into two groups according to the performance of primary tumor resection. Pearson's chi-square test, Kaplan-Meier survival curve, and Cox regression analysis were conducted in this study. In addition, propensity-score matching was conducted to match 323 patients who received primary tumor resection and another 323 patients without.Results: Multivariate Cox regression analysis demonstrated that primary tumor resection was a significant prognostic factor in patients with metastatic AEG before matching. Moreover, in the matched cohort, metastatic AEG patients receiving primary tumor resection had significantly longer overall survival (hazard ratio [HR]: .54, 95% confidence interval [CI]: .46-.64, P < .001) and cancer-specific survival (HR: .53, 95% CI: .45-.63, P < .001). Subgroup analysis similarly revealed that primary tumor resection was significantly associated with better survival in most subgroups.Conclusion: The present population-based study identified that primary tumor resection led to significantly superior survival in patients with metastatic AEG. These findings are likely to contribute to the development of individualized therapy in metastatic AEG.