Prophylactic Intraperitoneal Chemotherapy with Platinum Agents Following Curative Resection for Colorectal Cancer: A Systematic Review and Meta-Analysis.

Abstract

Peritoneal recurrence is a significant concern after curative resection of colorectal cancer (CRC), with systemic chemotherapy providing limited prevention. Prophylactic intraperitoneal chemotherapy (PIC) using platinum-based agents offers a potential strategy to reduce recurrence and improve survival. Our objective was to assess the effectiveness of platinum-based PIC in reducing peritoneal recurrence and enhancing survival outcomes when administered during or after curative CRC resection versus surgery alone or standard systemic therapy. We conducted a systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Databases were searched from January 2015 to September 2025 for randomized and comparative studies of adults receiving curative CRC resection with platinum-based PIC versus controls. Primary outcomes were overall survival (OS), disease-free survival (DFS), and peritoneal recurrence. Secondary outcomes were grade 3-4 adverse events and major complications. Random-effects meta-analyses in R used hazard ratios (HRs) for time-to-event outcomes and risk ratios (RRs) for binary outcomes; heterogeneity was assessed via I². In total, 16 studies were included in the qualitative synthesis and seven (three randomized controlled trials, four cohorts; n=1264) in the meta-analysis. Platinum-based PIC improved DFS (HR 0.57; 95% confidence interval [CI] 0.42-0.78, p=0.0004, I²=0%) and trended toward an OS benefit (HR 0.87; 95% CI 0.69-1.12, p=0.28, I²=0%). Peritoneal recurrence was reduced but heterogeneous (RR 0.69; 95% CI 0.29-1.63, p=0.40, I²=85%). No increases were observed in grade 3-4 events (RR 1.26; 95% CI 0.97-1.64, p=0.08, I²=0%) or complications (RR 1.02; 95% CI 0.74-1.39, p=0.91, I²=39%). Platinum-based PIC appears to enhance DFS without increasing adverse events or complications. Larger randomized controlled trials with longer follow-up are needed to confirm potential survival benefits and determine optimal protocols.