The absence of benefit of perioperative chemotherapy in initially resectable peritoneal metastases of colorectal cancer origin treated with complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: A retrospective analysis

Introduction: The aim of this study was to compare the outcome of patients with peritoneal metastasis (PM) of colorectal origin treated with complete cytoreductive surgery (CRS) and hyperthermic intra-peritoneal chemotherapy (HIPEC) with or without perioperative systemic chemotherapy (PCT+/PCT-). Patients and methods: Retrospective analysis of 125 patients treated with complete CRS (R0/R1) and HIPEC for PM from colorectal origin in two Belgian academic centers between 2008 and 2017. Disease-free survival (DFS) and overall survival (OS) were assessed with regard to PCT. Statistical analyses were adjusted for non-balanced survival risk factors. Results: The PCT+ group (n = 67) received at least 5 cycles of PCT and the PCT-group (n = 56) did not receive PCT. The groups were well balanced for all prognostic factors except presentation of synchronous disease (more in PCT+). Survival analysis was adjusted to peritoneal cancer index and presentation of synchronous disease. After a median follow-up of 54 +/- 5-months, the 1, 3, 5-years OS in the PCT+ group were 98%, 59% and 35% compared to 97%, 77% and 56% in the PCT-group (HR = 1.46; 95% CI:0.87-2.47; p = 0.155). The 1,3 and 5 years DFS in the PCT+ group were 47%, 13% and 6% compared to 58%, 29% and 26% respectively in the PCT-(HR = 1.22; 95% CI:0.78-1.92; p = 0.376). Conclusion: This study does not show any clear benefit of PCT in carefully selected patients undergoing R0/R1 CRS and HIPEC for colorectal PM. The ongoing CAIRO6 trial randomizing CRS/HIPEC versus CRS/ HIPEC and PCT will probably clarify the role of PCT in patients with resectable PM. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The study compared the outcomes of patients with colorectal peritoneal metastasis treated with complete CRS and HIPEC with or without perioperative systemic chemotherapy (PCT). Results showed no clear benefit of PCT in terms of survival rates. Further research, including ongoing trials, is needed to clarify the role of PCT in patients with resectable PM.