Catheter-based liver therapies represent a cornerstone of interventional oncology. The fundamental mechanism relies on the unique dual blood supply of the human liver: healthy liver tissue, known as parenchyma, receives roughly 75% of its blood flow from the portal vein, whereas malignant liver tumors derive over 80% to 90% of their blood supply from the hepatic artery. By selectively cannulating the arterial branches feeding the tumor, interventional radiologists deliver microscopic treatment agents directly into the lesion. Transarterial chemoembolization combines concentrated chemotherapy with blood vessel blockages called embolic agents to starve the tumor of oxygen and trap toxins within the malignant growth. Yttrium-90 radioembolization (Y-90), also termed transarterial radioembolization (TARE), releases localized beta radiation through embedded radioactive microspheres to damage tumor DNA. These targeted therapies aim to control tumor growth, downstage advanced tumors for potential liver transplantation or surgical resection, and extend survival while preserving quality of life.

The patient is positioned on the fluoroscopy table and given intravenous sedation and local anesthesia over the access artery. The interventional radiologist accesses the femoral artery in the groin or radial artery in the wrist using micro-puncture technique. A microcatheter is navigated under real-time X-ray guidance into the main hepatic artery and selectively advanced into the specific arterial branches supplying the tumor. Contrast dye injections (angiography) confirm blood vessel layout and tumor hypervascularity. For TACE, chemotherapy emulsified in lipiodol or loaded into drug-eluting beads is infused, followed by embolic microspheres until arterial blood flow slows to a halt. For Y-90, pre-calculated doses of radioactive microspheres are injected directly into the tumor-feeding vessels. The catheter is removed, and a closure device or manual compression is applied to the arterial puncture site. The total procedure duration ranges from 60 to 120 minutes.

Evidence-based clinical benefits of TACE and Y-90 radioembolization include:

• Targeted destruction of liver tumors with minimal damage to healthy liver tissue and decreased systemic side effects compared to intravenous systemic chemotherapy.
• Extension of overall survival in intermediate-stage hepatocellular carcinoma, confirmed by pivotal clinical trials (Llovet et al., 2002; Salem et al., 2016).
• Ability to bridge patients waiting for a liver transplant, keeping them within Milan criteria and preventing drop-off from organ waiting lists.
• Successful downstaging of unresectable tumors to allow secondary surgical resection or curative thermal ablation.
• High rates of localized disease control and rapid relief from clinical symptoms caused by neuroendocrine hormone-secreting metastases.
• Outpatient or short overnight stay with minimal recovery downtime compared to open abdominal surgery.

Recovery following intra-arterial liver therapy varies based on the underlying hepatic reserve and procedure type. Immediate recovery involves 2 to 6 hours of flat bedrest to prevent bleeding at the arterial access site in the groin or wrist. Most patients experience mild to moderate post-embolization syndrome, characterized by fatigue, low-grade fever, nausea, and right upper quadrant abdominal pain. These symptoms typically peak within 48 to 72 hours and resolve within 7 to 14 days with oral antiemetics and analgesics. Most individuals return to light daily activities within 3 to 5 days and full physical activity within 2 weeks. Laboratory monitoring of liver enzymes and function occurs at 2 to 4 weeks, followed by cross-sectional imaging (CT or MRI) at 1 to 3 months to evaluate treatment response using specialized response criteria.

Transarterial therapies primarily treat primary liver cancers and select secondary malignant tumors that have metastasized to the liver. Key indications include:

• Hepatocellular carcinoma (HCC), particularly Barcelona Clinic Liver Cancer (BCLC) intermediate stage (Stage B) tumors.
• Intrahepatic cholangiocarcinoma (iCCA), or cancer originating within the bile ducts inside the liver.
• Metastatic colorectal cancer (mCRC) with liver-predominant metastases that are non-resectable or resistant to systemic chemotherapy.
• Neuroendocrine tumor liver metastases (NETLM) causing symptomatic hormone hypersecretion or bulk tumor progression.
• Uveal melanoma metastases and select breast cancer or gastrointestinal stromal tumor (GIST) liver metastases.

Preparation begins with diagnostic blood tests assessing blood counts, coagulation status, liver function, and kidney performance. A diagnostic multiphase CT or contrast-enhanced MRI is performed to map tumor burden and arterial anatomy. For Y-90, a preliminary mapping angiogram is conducted 1 to 2 weeks prior, involving the administration of Technetium-99m macroaggregated albumin (99mTc-MAA) followed by a SPECT/CT scan to calculate the lung shunt fraction and check for unintended GI tract flow. Patients fast for 6 to 8 hours prior to the procedure. Blood-thinning medications are held under specialist guidance, and intravenous hydration is initiated prior to arterial catheterization.

Common and mild side effects include post-embolization syndrome (fatigue, low-grade fever, nausea, abdominal pain) occurring in up to 80% of patients. Vascular access complications include groin or wrist hematoma (2-5%) and pseudoaneurysm (<1%). Serious but uncommon risks include transient acute liver injury or hepatic decompensation (3-8%), acute cholecystitis from non-target embolization of the cystic artery (1-2%), and contrast-induced acute kidney injury (1-3%). Rare but severe complications (<1%) include radiation-induced liver disease (RILD), irreversible liver failure, non-target embolization causing gastrointestinal ulceration or pancreatitis, radiation pneumonitis from lung shunting, and severe sepsis or liver abscess formation.

The treatment journey for TACE or Y-90 begins with a multidisciplinary liver tumor board evaluation involving hepatologists, medical oncologists, surgical oncologists, and interventional radiologists. Patients undergo comprehensive blood testing and high-resolution imaging, such as magnetic resonance imaging (MRI) or multiphase computed tomography (CT). For Y-90 therapy, a preliminary diagnostic mapping angiography and lung shunt fraction assessment are performed 1 to 2 weeks before the procedure to ensure safety. On the treatment day, the patient receives local anesthesia and conscious sedation before a vascular catheter is threaded through the femoral or radial artery into the liver. The intervention lasts between 1 and 2 hours, followed by a brief period of post-procedure monitoring or an overnight hospital stay. Patients undergo structured imaging follow-up at 1, 3, and 6 months post-treatment to evaluate treatment response and guide further care.