ASO Visual Abstract: Treatment and Survival Outcomes of Patients with Colorectal Peritoneal Metastases Deemed Ineligible for Cytoreductive Surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC): Results of a Retrospective Study

Background Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment option for selected patients with colorectal peritoneal metastases (PM). This report provides an overview of treatment and survival outcomes for patients deemed ineligible for CRS-HIPEC. Methods Colorectal PM patients referred to a tertiary center from 2014 to 2020 that were ineligible for CRS-HIPEC were included. Patient, tumor, and treatment characteristics were provided. Survival analyses were performed using the Kaplan-Meier method. Results Of 476 patients referred for CRS-HIPEC, 227 (48%) were deemed ineligible. Median follow-up was 15 months [IQR 10–22]. Data on follow-up treatment was available for 198 patients, of which 73% received systemic therapy. These patients had a median overall survival (OS) of 17 months [IQR 9–25]. For patients receiving best supportive care (BSC) median OS was 4 months [IQR 2–9]. The main reason for ineligibility was extensive PM (42%), with a median OS of 11 months [IQR 5–18]. Patients deemed ineligible due to (extensive) liver (9%) or lung metastases (8%) showed longer OS (median 22 months, IQR 8–27, and 24 months, IQR 12–29, respectively) than patients with extensive PM (median 11 months, IQR 5–18) or distant lymph node metastases (median 14 months, IQR 4–25). Conclusion The main reason for CRS-HIPEC ineligibility was extensive PM. The majority of patients received systemic therapy. Patients deemed ineligible due to extra-peritoneal metastases had better survival outcomes than patients deemed ineligible due to extensive PM.