The encouraging preliminary results of radioembolization therapy in hepatocellular carcinoma and liver metastases from colorectal cancer have suggested that this mode of therapy could also be successful in breast and neuroendocrine metastases from colorectal cancer. (90)Yttrium microspheres in combination with radiosensitizing agents and growth factor inhibitors present opportunities to evaluate its application in combinatorial treatment paradigms with modern chemotherapy regimens. Other randomized trials are needed in hepatocellular carcinoma, to compare radioembolization with (90)yttrium against transarterial chemoembolization, bland embolization, drug-eluting beads, and best supportive care. A further potential research area besides the application of radioembolization for extrahepatic tumors is the determination of quality of life in randomized studies comparing radioembolization with systemic chemotherapy regimens with or without percutaneous radiation therapies.