Benefits of Surgery After Neoadjuvant Intraperitoneal and Systemic Chemotherapy for Gastric Cancer Patients With Peritoneal Metastasis: A Meta-Analysis

Conversion therapy is intended to allow achieving R0 resection after chemotherapy for tumors initially considered unresectable or partially resectable. Neoadjuvant intraperitoneal and systemic chemotherapy (NIPS) is the current conversion therapy for gastric cancer (GC) patients with peritoneal metastasis. This meta-analysis evaluated the effectiveness and safety of NIPS-combined surgery for GC patients with peritoneal metastasis.Standard methods were used to select and analyze studies that included GC patients with peritoneal metastasis assigned to two groups, either NIPS-combined surgery or a NIPS-only control. Publications were retrieved from PubMed, EMBASE, Medline, and the Cochrane Central Register. Overall survival, conversion therapy success and R0 resection rates, and adverse events were analyzed using Stata 11.0.Eight of the 14 studies that were evaluated after screening the titles and abstracts of 327 retrieved publications met the selection criteria. The eight retrospective studies included 373 patients with GC and peritoneal metastasis included 265 with NIPS-combined surgery and 109 with NIPS only. Survival was significantly better with NIPS-combined surgery than with NIPS only (hazard ratio = 0.440, 95% confidence interval [CI]: 0.274-0.704; P = 0.0001; odds ratio = 1.960; 95% CI: 1.247-3.083; P = 0.004). Subgroup analysis revealed significantly better survival with S-1 Joint intravenous paclitaxel and intraperitoneal paclitaxel compared with other NIPS regimens. NIPS regimens had a higher conversion rate (effect size [ES] = 0.656; 95% CI: 0.495-0.817; P < 0.05), higher percentage of patients with R0 surgery (ES = 0.633; 95% CI: 0.568-0.699; P < 0.05), less severe adverse reactions to chemotherapy (ES = 0.030; 95% CI: 0.020-0.040; P < 0.05), and fewer postoperative complications (ES = 0.040; 95% CI: 0.020-0.050; P < 0.05).NIPS-combined surgical treatment was effective and safe for treating GC with peritoneal metastasis. Higher quality trials, better patient selection, and multicenter randomized controlled trials are needed to support standard treatment guidelines.