# Iterative Cytoreductive Surgery and HIPEC for Peritoneal Metastases from Primary Appendiceal and Colorectal Cancers: An Observational Study

## TL;DR

Repeat surgery and chemotherapy can help some cancer patients survive longer after cancer returns in the abdomen.

## Contribution

This study shows repeat CRS/HIPEC is safe and effective for appendiceal cancer recurrence but not for colorectal cancer.

## Key findings

- Repeat CRS/HIPEC achieved complete cytoreduction in 79% of appendiceal cancer patients.
- Appendiceal cancer patients had significantly improved survival after repeat CRS/HIPEC.
- Colorectal cancer patients did not show improved survival with repeat CRS/HIPEC.

## Abstract

Peritoneal relapse after cytoreduction and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is common. Repeat CRS/HIPEC offers the potential for long-term survival in the appropriately selected patient. We examined the outcome for appendiceal and colorectal cancer patients who underwent repeat CRS/HIPEC after isolated peritoneal recurrence. Repeat CRS/HIPEC was safe and associated with the potential for a long-term survival outcome, particularly for appendiceal cancer.

Background: Peritoneal relapse after cytoreduction and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is common. Repeat CRS/HIPEC offers the potential for long-term survival in the appropriately selected patient. Methods: We performed a retrospective review of a single institution database to assess perioperative outcomes after repeat CRS/HIPEC for appendiceal (pAC) and colorectal (pCRC) cancers. Kaplan–Meier and Cox estimates were used to assess survival. Results: Of 157 patients, 103 patients underwent initial CRS/HIPEC for pAC (n = 67) or pCRC (n = 36) histologies. Twenty-seven pAC patients (27/67, 40%) and 23/36 pCRC patients (63%) developed disease recurrence. Relapsed patients had a higher burden of disease (PCI), operative length and blood loss and received adjuvant chemotherapy (all p < 0.05). Nine of the 27 relapsed pAC patients and 5 of the 13 relapsed pCRC patients underwent repeat CRS/HIPEC. The median time to repeat CRS/HIPEC was 18 months (4–26 months), and a CCR-0 and CCR-1 were achieved in 79% and 21%, respectively. The 1-, 3- and 5-year OS for pAC patients who underwent repeat CRS/HIPEC was 88.9%, 88.9% and 77.8%, and the 1- and 3-year OS for pCRC patients was 100% and 25%, respectively. Repeat CRS/HIPEC for pAC was associated with significant improvement in OS (p = 0.03), while for pCRC, no significant difference was observed (p = 0.99). Conclusions: Repeat CRS/HIPEC for isolated peritoneal recurrence is safe and offers the potential for long-term survival. Patient selection is key to ensure optimal cytoreduction when considering repeat CRS/HIPEC.