Comparison of survival between liver-only metastasis and other metastatic sites in patients with de novo stage 4 gastric cancer: Nationwide data from a single institute.

Abstract

e16044 Background: Although recent studies have shown a steady decline in the incidence and mortality over the past several decades, Gastric cancer (GC) remains the fourth major cause of cancer related mortality. Stage 4 GC is an advanced stage of disease, as cancer spreads to other parts of the body. In this study, we aim to investigate whether 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 2018 and December 2020 Demographic summary of patients, any co-morbidities, treatment, and tumor-related data was extracted and analyzed using statistical software. We generated three groups, each including patients with metastasis to only one 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 4 gastric cancer (Table 1). Of those, majority (69%) were male, and 55% from Asia, followed by MENA regions (29.9%). As for differentiation, around 67% had poorly differentiated GC (Table 1). Table 2 shows the results for patients with GC with only one site of metastasis: Liver, Peritoneum, and rpln. Those with only metastasis to the liver were on average older (64 (54.5 – 68.0), p = 0.074). Liver metastasis was more likely to occur in male compared to females (p = 0.012). The Kaplan-Meier curve showed a statistically significant 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 peritoneal metastasis alone had a 2.87-fold (95% CI 1.03 – 7.97, p = 0.043) increase in hazard of mortality compared to liver metastasis alone. Patients with rpln had similar survival compared to liver metastasis. Conclusions: This study shows that patients with only liver or rpln metastasis have a better median overall survival compared to peritoneal. As our data is from a single center, further analysis on large cohorts in needed to validate the findings.