Surgical Management for Colorectal Peritoneal Metastases

Abstract

Colorectal peritoneal metastasis (CPM) has long been considered a terminal condition with poor prognosis, due to its diffuse spread and limited responsiveness to systemic chemotherapy. However, recent advances in surgical strategies have changed this perspective. In Western countries, in appropriately selected patients, cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has achieved 5-year survival rates of 30-45%, and is becoming established as a standard treatment. CRS aims to remove all visible tumors, and HIPEC targets microscopic residual disease with heated intraperitoneal chemotherapy, offering pharmacokinetic advantages. Prognostic indicators such as the Peritoneal Cancer Index (PCI) and completeness of cytoreduction (CC) score are key for patient selection, and refined diagnostic approaches such as staging laparoscopy and advanced imaging are increasingly being utilized. Recent randomized controlled trials have reported that the additional benefit of HIPEC has not been clearly demonstrated. In Japan, the mainstay treatment remains localized peritonectomy (tumor debulking) for limited CPM (P1/P2), which also shows favorable outcomes. However, CRS+HIPEC is still limited to specialized centers. In future, further accumulation of evidence and validation through prospective comparative trials are essential to optimize treatment selection and expand the role of CRS+HIPEC in Japan.