Does Malignant Ascites Define Prognosis in Gastric Cancer with Peritoneal Spread? A Systematic Review and...

Gastric cancer (GC) is the fifth most common cancer and a leading cause of cancer-related death. Peritoneal metastases occur in up to 25% of patients, with nearly half developing malignant ascites (MA), which arises from lymphatic obstruction, vascular permeability, and immune dysregulation. Median overall survival (OS) in this setting is poor (2-8 months). This systematic review and meta-analysis evaluate the prognostic impact of ascites in metastatic GC.

PubMed, Embase, and Cochrane were searched for studies reporting OS in metastatic GC patients with and without ascites. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using fixed and random-effects models in RStudio 4.2.3.

Overall, 14 studies involving 2179 patients, with 1208 having ascites, were included in the analysis. Of these, 13 were retrospective studies and 1 was a prospective study. The presence of ascites was associated with a significantly worse prognosis compared to its absence (HR 1.8418; 95% CI 1.5657-2.1667; P < 0.001). Similarly, the comparison of massive type ascites with mild to moderate type shows a worse outcome for the higher grade of ascites (HR 1.8597; 95% CI 1.4633-2.3635; P < 0.001). Comparing no to moderate ascites vs massive ascites, the massive type also shows a significantly lower overall survival (HR 2.5114; 95% CI 1.5409-4.0931; P < 0.001).

This meta-analysis suggests that the presence of ascites and its grades are essential prognostic factors for metastatic gastric cancer, significantly worsening overall survival.