Comparative Radiologic Response Assessment after Transarterial Chemoembolization, Percutaneous Ablation, and Multimodal Treatment: Radiologic-Pathologic Correlation in 81 Tumors.

Purpose: To compare concordance of radiologic and pathologic response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE), percutaneous ablation, and multimodal treatment using radiologic-pathologic correlation.

Materials and methods: This single-center retrospective study analyzed 56 treatment-naive patients (male, 75%; Barcelona Clinic Liver Cancer Stage A, 63%) with 81 HCC tumors (mean diameter, 2.1 cm [SD ± 0.9]) who underwent locoregional therapy (LRT) (TACE, n = 44; ablation, n = 10; TACE + ablation, n = 27) prior to liver transplantation (LT) between 2010 and 2019. Immediate pre-LT cross-sectional imaging was used to assess modified Response Evaluation Criteria in Solid Tumours (mRECIST) response. Explant liver pathology was reviewed for percent pathologic necrosis (PN). Associations between imaging and pathologic observations were statistically characterized using the chi-square and Kruskal-Wallis tests.

Results: Median time from imaging to LT was 37 days (range, 2-191 days). Across all LRT types, 68% (55/81), 19% (15/81), and 13% (11/83) of tumors displayed mRECIST complete response (CR), partial response (PR), and stable disease. The mean percent PN (%PN) in CR tumors (89% [SD ± 21]) was significantly higher than those in PR (68% [SD ± 34], P = .005) and stable disease (67% [SD ± 36], P = .009) tumors. Sixty percent (33/55) of CR tumors showed 100% complete PN (CPN), whereas only 20% (3/15) of PR tumors and 18% (2/11) of stable disease tumors showed CPN (P = .002). There was no association between %PN and CPN across different LRT modalities and radiologic response categories, indicating consistent performance between treatments. Sensitivity and specificity for radiologic CR to predict 100% PN were 87% and 49%, respectively.

Conclusions: Herein, radiologic-pathologic outcomes suggest that radiologic response criteria are associated with PN, with no differences across treatment modalities. However, the imperfect predictive capacity of imaging for PN supports surveillance of treated tumors before LT.