Regional Therapy for Colorectal Cancer Liver Metastases: Which Modality and When?

For patients with unresectable colorectal liver metastases (uCRLM), regional therapies leverage the unique, dual blood supply to the liver; the hepatic artery is the main blood supply for liver tumors, whereas the portal vein supplies most normal hepatic parenchyma. Infusion of cancer therapies via the hepatic artery allows selective delivery to the tumors with relative sparing of normal liver tissue and little extrahepatic exposure, thus limiting systemic side effects. There is a paucity of randomized controlled trial evidence to inform the optimal integration of regional therapies into the management of CRLM. Hepatic arterial infusion pump (HAIP) chemotherapy has a potential survival benefit when used in the adjuvant setting after resection of CRLM. HAIP chemotherapy can be safely given with contemporary systemic therapies and is associated with a high objective response and rate of conversion to resectability in patients with uCRLM. Drug-eluting beads coated with irinotecan transarterial chemoembolization is associated with high objective response rates within the liver and has a well-established safety profile in patients with uCRLM. Transarterial radioembolization achieves high rates of response within the liver but is not associated with improvements in overall survival or quality of life in the first- or second-line setting for uCRLM. The best treatment approach is the one that most aligns with a given patients' values, preferences, and philosophy of care. In the first-line setting, HAIP could be offered to motivated patients who hope to achieve conversion to resectability. After progression on chemotherapy, HAIP, transarterial chemoembolization, and transarterial radioembolization are valuable treatment options to consider for patients with liver-limited or liver-predominant CRLM who seek to optimize response rates and regional control.