Histopathologic Response and Oncologic Outcomes after Segmental and Subsegmental Transarterial Chemoembolization and Radioembolization for Hepatocellular Carcinoma

Purpose: To compare histopathologic outcomes of transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) and determine predictors of complete pathologic necrosis (CPN). Materials and Methods: Patients with hepatocellular carcinoma treated with segmental (≤2 segments) or subsegmental TACE or TARE and underwent liver transplantation between January 2014 and March 2022 at a single center were retrospectively reviewed. Histopathologic and posttransplant outcomes were assessed within 2 years. Multivariable logistic regression, propensity score matching (PSM), and Kaplan-Meier survival analysis were performed. Results: A total of 208 tumors in 148 patients were treated with segmental or subsegmental TACE (n = 76) or TARE (n = 132). In total, 132 tumors (63.5%) achieved CPN, and 156 (75.0%) had >90% necrosis on explant. The CPN rates by tumor in the TACE and TARE cohorts were 29.0% and 83.3%, respectively (P < .0001). Target tumor complete radiologic response (modified Response Evaluation Criteria in Solid Tumours) after TARE had a higher positive predictive value (89.0%) for CPN than that after TACE (42.9%). PSM analysis of TACE and TARE demonstrated that independent predictors of CPN were time from last treatment to transplant, subsegmental injection, and TARE. Patients who achieved overall CPN had significantly longer recurrence-free survival at 2 years (P = .02). Conclusions: In a cohort of patients who were bridged or downstaged to LT, there was improved recurrence-free survival in those who achieved CPN. Overall, TARE was superior to TACE in achieving pathologic necrosis.