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Transarterial radioembolization (TARE), also called Selective Internal Radiation Therapy (SIRT), is a locoregional therapy for liver malignancies in which microspheres loaded with a radioactive isotope (commonly Yttrium-90, Y-90) are delivered via the hepatic arterial circulation.

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This provides targeted internal radiation to hepatic tumors while sparing much of the normal liver.

Rationale

• Tumor biology: Liver tumors (HCC, metastases) derive most of their blood supply from the hepatic artery, while normal hepatocytes are mainly supplied by the portal vein.
• Concept: Delivering radioactive microspheres via the hepatic artery → preferential lodgment in tumor capillary bed → high-dose beta radiation → local tumor necrosis, with limited systemic toxicity.

Indications

Primary

• Unresectable hepatocellular carcinoma (HCC), especially with portal vein thrombosis (contraindication for TACE).
• Intrahepatic cholangiocarcinoma.

Secondary (metastatic)

• Colorectal liver metastases (chemo-refractory).
• Neuroendocrine tumor liver metastases.
• Breast, melanoma, and other metastases (selected cases).

Other roles

• Bridging therapy before liver transplantation.
• Downstaging tumors to resection/transplant criteria.

Contraindications