Results of complete cytoreductive strategy in patients with peritoneal metastases of colorectal origin with or without extraperitoneal metastases: A bicentric analysis

Background: Increased survival can be achieved in patients with colorectal cancer peritoneal metastases (CRPM) treated with cytoreductive surgery. The benefit of this strategy remains uncertain when CRPM are associated with extraperitoneal metastases (EPM). The aim of this study was to compare short- and long-term outcomes of patients treated with CRS for CRPM, with or without EPM. Methods: This study included 413 consecutive patients who underwent CRS for CRPM: 120 with EPM (EPM+) and 293 without (EPM-). Patients with isolated ovarian metastases were included in EPM-group (n = 83). Results: EPM were mainly located to the liver (66 %,n = 79), retroperitoneal lymph nodes (33 %,n = 40); less frequently to the spleen (9 %,n = 12), lung (9 %,n = 10) or pleura (1 %,n = 1). Ovarian metastases were present in 126 patients (83 in EMP-, 43 in EPM+). Peritoneal carcinomatosis index (PCI) was similar in EPM- (8 [4–14]) and EPM+ (8 [3–13],p = 0.335) groups, as postoperative mortality (3 % vs 3 %,p = 1) and major morbidity rates (28 % vs 35 %,p = 0.223). Median overall survival (mOS) and disease-free survival were significantly higher in the EPM-group (58m vs 39m, and 16m vs 10m,p = 0.003). We highlighted 3 prognostic groups 1) EPM-with PCI<10 (mOS 93m), 2) EPM+ with PCI<10 (mOS 57m), 3) EPM-with 10<PCI<15 (mOS 35m) or EPM+ with 10<PCI<15 (mOS 31m) or PCI>15 regardless EPM (mOS 26m, p < 0.001). Conclusion: Complete cytoreductive surgery seems to be feasible in patients with EPM, without increase in postoperative morbidity and mortality compared to patients without EPM. This strategy provides prolonged survival in selected patients with limited peritoneal metastases from colorectal cancer.