by Michael Petroziello, MD
Assistant Professor of Oncology, Diagnostic Imaging, Department of Diagnostic Radiology
The management of hepatocellular carcinoma (HCC) requires a careful multidisciplinary approach utilizing medical oncologists, surgeons and interventional radiologists. Treatment options require assessment of tumor stage, liver function and performance status. The Barcelona Clinic Liver Cancer (BCLC) staging system is the most widely accepted staging system in clinical practice for prognosis prediction and treatment allocation. Treatment options vary depending on clinical stage (0-D) and include curative options for very early and early patients and palliative options for intermediate stage and advanced patients.
Surgical resection remains the first-line treatment for patients with solitary tumors and preserved liver function. Unfortunately, only 10–20 percent of patients are candidates for resection due to tumor burden, the presence of extrahepatic spread or the extent of underlying liver disease. For patients who are not candidates for surgical resection, liver transplantation is the first-line treatment if the tumor characteristics are within transplant criteria.
Outside of surgical resection, the role of interventional radiology in the treatment of HCC continues to grow as novel non-invasive treatment techniques are developed and refined. For patients with early stage HCC who are not candidates for resection, percutaneous thermal ablation demonstrates favorable results for tumors less than 3 cm. While radiofrequency ablation (RFA) has the most substantial track record, the advent of microwave ablation has resulted in greater ablation zones, decreased patient pain and fewer detrimental treatment effects on adjacent blood vessels. Unfortunately, a population of patients remains ineligible for thermal ablation because of tumor proximity to main biliary tracts. However, irreversible electroporation (IRE), which uses pulsed direct current to induce cell death, has been shown to be effective in tumors adjacent to major bile ducts where standard thermal ablation techniques are contraindicated.
Conventional transarterial chemoembolization (TACE) utilizing a chemotherapeutic agent mixed with oil is the recommended first-line therapy in intermediate stage disease. Studies have demonstrated improved overall survival for TACE compared with best supportive care in patients with HCC and preserved liver function. Additionally, with the advent of drug eluting beads (DEB) instead of oil, higher doses of chemotherapy can be administered and liver toxicities are reduced.
Radioembolization with yttrium-90 loaded beads is an alternative transarterial treatment option in patients with intermediate stage HCC. Radioembolization has been shown to have similar treatment efficacy and safety profile when compared to chemoembolization. Additionally, radioembolization is safe and effective in a sub-segment of patients with advanced HCC and portal vein invasion. Furthermore, both radioembolization and chemoembolization can be safely combined with the systemic agent sorafenib to improve outcomes in advanced patients.
Newer concepts in radioembolization include radiation segmentectomy, whereby selective transarterial treatment of the tumor with high doses of radiation result in eradication of the tumor while sparing normal liver parenchyma from non-target radiation. Furthermore, the concept of radiation lobectomy has been designed to replace portal vein embolization prior to surgical resection. Delivering high doses of radiation to the lobe which is to be resected not only treats the tumor but also induces contralateral hypertrophy to improve post-resection hepatic reserve.
Effective treatment of primary liver tumors involves a multidisciplinary approach. As non-invasive therapies continue to advance, the role of the interventional radiologist within the HCC treatment algorithm will continue to expand.