Chemoembolization for unresectable hepatocellular carcinoma in Japan

Area of Science:

• Hepatobiliary Oncology
• Interventional Radiology
• Cancer Treatment Efficacy Assessment

Background:

• Hepatocellular carcinoma (HCC) is frequently treated with transcatheter arterial chemoembolization using lipiodol (Lip-TACE).
• Superselective Lip-TACE aims to maximize therapeutic effect and minimize non-cancerous liver injury.
• Recurrence rates after Lip-TACE highlight the need for effective treatment and accurate outcome assessment.

Purpose of the Study:

• To evaluate the therapeutic effect (TE) of Lip-TACE based on tumor size and pathological findings.
• To assess the correlation between radiologic and pathologic assessment of tumor necrosis post-Lip-TACE.
• To examine the utility of WHO criteria in evaluating Lip-TACE treatment response.

Main Methods:

• Analysis of treatment data from the Liver Cancer Study Group of Japan (LCSGJ) report.
• Pathologic examination of 26 resected HCC specimens treated with Lip-TACE to determine necrosis rates.
• Comparative study correlating radiologic necrosis (CT) with pathologically proven necrosis.
• Evaluation of treatment response using proposed modified assessment criteria focusing on tumor necrosis and regression.

Main Results:

• Local recurrence rates for single-session Lip-TACE in HCC ≤5 cm ranged from 33-38% at 3 years.
• Pathologic analysis showed significantly higher necrosis rates and complete necrosis in smaller HCCs (<3 cm) compared to larger ones.
• A good correlation was observed between radiologic and pathologic necrosis when lipiodol retention indicated necrosis, but poor correlation when it suggested viable tumor.
• No correlation was found between pathologic necrosis rate and tumor size reduction by WHO criteria.

Conclusions:

• Tumor size is a critical factor influencing the therapeutic effect of Lip-TACE, with smaller tumors yielding better outcomes.
• Radiologic assessment of necrosis post-Lip-TACE using CT may be unreliable, particularly when lipiodol retention is misinterpreted.
• Modified assessment criteria incorporating tumor necrosis and regression are proposed for more accurate evaluation of Lip-TACE efficacy.