Impact of Omission of Hyperthermic Intraperitoneal Chemotherapy for Treatment of Colorectal Peritoneal Metastases

INTRODUCTION: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have traditionally been the treatment for colorectal peritoneal metastasis (CPM). PRODIGE 7, a French multicenter trial, showed no survival difference with the addition of HIPEC to CRS but showed increased morbidity. With substantial differences between US and French HIPEC regimens, validity of PRODIGE 7 in US practice has been questioned with concern that omission of HIPEC will result in undertreatment. Given these controversies, the authors evaluated their experience of CRS with and without HIPEC in patients with CPM to compare morbidity, recurrence patterns, and overall survival (OS). METHODS: Retrospective cohort study was performed to evaluate patients with CPM undergoing CRS with or without HIPEC within a single health care system. HIPEC regimen was mitomycin-C/90 min. RESULTS: Thirty patients with CPM were identified; 23 underwent CRS-HIPEC, while 7 underwent CRS only. Between groups, there were no differences in age, sex, surgical or systemic treatment history, preoperative carcinoembryonic antigen levels, and time from diagnosis of CPM to surgery. There was no difference in peritoneal cancer index scores, regions affected by CPM, resected organs, and operative time. There was no difference in length of stay, surgical reinterventions, and all 30-day morbidity. There was no difference in 1-year OS. DISCUSSION: With addition of HIPEC-mitomycin to CRS, patients had longer time to return to regular diet and intensive care unit length of stay, without difference in 1-year OS. CONCLUSION: CRS with mitomycin-HIPEC can be considered for treatment of CPM without significant morbidity and equivalent short-term oncologic benefits. However, the long-term benefit of HIPEC remains unclear.