Efficacy of additional hyperthermic intraperitoneal chemotherapy for gastric cancer with peritoneal metastasis: an updated systematic review and meta-analysis.

BACKGROUND: The survival benefit of hyperthermic intraperitoneal chemotherapy (HIPEC) in gastric cancer with peritoneal metastasis (PM) remains controversial. This study evaluates the efficacy of HIPEC in these patients. METHODS: We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library (from inception to August 2026) to identify randomized controlled trials (RCTs) and cohort studies evaluating the efficacy of HIPEC in gastric cancer with PM. The primary endpoint was overall survival (OS). Pooled hazard ratios (HRs) and 95% confidence intervals (95%CIs) were calculated using a random-effects model. The study protocol was registered in PROSPERO (CRD420261332944). RESULTS: Nine studies, including four RCTs and five cohort studies, were included in the meta-analysis. Patients receiving additional HIPEC had significantly better OS than those in the control group (HR = 0.71, 95%CI: 0.56-0.91; p = 0.008). In subgroup analyses, patients receiving additional HIPEC showed better OS than those in the control group in studies combined with cytoreductive surgery (CRS) (HR = 0.64, 95%CI: 0.50-0.80; p < 0.001), Western studies (HR = 0.67, 95%CI: 0.53-0.85; p < 0.001), and cohort studies (HR = 0.63, 95%CI: 0.55-0.72; p < 0.001). In contrast, studies using additional HIPEC showed no significant OS benefit in RCTs, Eastern studies, studies without CRS, or the subgroups defined by HIPEC drug regimen. CONCLUSIONS: In the overall analysis, additional HIPEC was associated with longer OS in patients with gastric cancer and PM, particularly in studies in which HIPEC was combined with CRS. However, the apparent survival benefit was mainly observed in observational cohort studies and was not confirmed in the pooled analysis of RCTs.