Clinicopathological Characteristics, Prognosis, and Survival Outcomes of Advanced Stage Gastric Cancer with Single- Site Metastasis: Nationwide Real-World Data from Qatar

Introduction: Although recent studies have shown a steady decline in mortality over the past several decades, Gastric cancer (GC) remains the fifth major cause of cancer-related mortality. Several prognostic factors, both patient- and tumor-related have been investigated as predictors for survival in patients with stage 4 GC. Aim : In this study, we aim to investigate whether the site of metastasis in patients newly diagnosed with stage 4 GC is a predictor for length of survival. Methods : This is a retrospective cohort study of patients treated at the National Center for Cancer Care and Research, Doha, Qatar. The data was collected between January 2015 and December 2020. We generated three groups, each including patients with metastasis to a single site: liver, peritoneum, or retroperitoneal lymph nodes (RPLN). A Kaplan-Meier survival graph was used to illustrate the overall survival of patients in the three groups. Cox proportional-hazard model was used to investigate whether site of metastasis is a predictor for overall survival. Results : A total of 134 patients with a median age of 52 (42 – 63) were diagnosed with stage IV GC. As for differentiation, around 67% had poorly differentiated GC. Of the 134 patients with Stage IV GC, 40 patients had single-site metastasis to either the liver, peritoneum, or RPLN. The Kaplan-Meier curve showed a statistically divergent increase in median overall survival (mOS) in patients with metastasis to the liver compared to peritoneum (20 vs 7, p = 0.03). Furthermore, patients with peritoneum-only metastasis had a 2.87-fold (95% UI 1.03 – 7.97, p = 0.043) increased mortality compared to liver-only metastasis. Patients with RPLN-only had similar survival compared to liver-only metastasis. Conclusion : This study shows that patients with liver-only or RPLN-only metastasis have a better mOS compared to peritoneal. As our data is from a single center, further analysis of large cohorts is needed to validate the findings.