Results of curative strategy in patients with peritoneal and extraperitoneal metastases from colorectal cancer

Abstract

Background: Curative treatment of peritoneal metastases from colorectal cancer (CRPM) relies on cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Benefits of this strategy remain uncertain when CRPM are associated with extraperitoneal metastases (EPM). The aim of this study was to compare outcomes of patients treated with CRS/HIPEC for CRPM, with or without EPM. Methods: This study included 331 consecutive patients undergoing CRS/HIPEC for CRPM: 100 patients with EPM (EPM+) and 231 patients with isolated peritoneal carcinomatosis (EPM-). Patients with ovarian metastases and no other EPM were included in EPM- group (n=75). Results: EPM were mainly located to the liver (75%,n=75) and retroperitoneal lymph nodes (31%,n=31), and less frequently to the spleen (10%,n=10), lung (4%,n=4) or pleura (1%,n=1). Thirty-nine patients (39%) in EPM+ had also ovarian metastases. Peritoneal carcinomatosis index (PCI) was similar in EPM- (8[4-14]) and EPM+ (8[4-14], p=0.964), as were mortality (3% vs 4%, p=0.906) and major morbidity rates (26% vs 33%, p=0.241). Median overall survival (mOS) and disease-free survival were significantly higher in EPM- (56 vs 33 months, and 17 vs 10 months, p< 0.01). We highlighted 3 prognostic groups 1) EPM- with PCI< 10 (mOS 98months), 2) EPM- with 10< PCI< 15 (mOS 49months) or EPM+ with PCI< 10 (mOS 52months, p=0.534), 3) EPM+ with 10< PCI< 15 (mOS 29months) or PCI>15 whatever EPM (mOS 28months, p=0.842). Conclusion: CRS/HIPEC is feasible in patients with EPM, without increasing postoperative morbidity and mortality compared to patients without EPM. This curative strategy provides prolonged survival in selected patients with limited CRPM (PCI< 10).