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. METHODS: This single-center retrospective study analyzed 56 treatment naive patients (75% male
63% BCLC A) with 81 HCC tumors (mean diameter 2.1±0.9 cm) who underwent locoregional therapy (LRT) (TACE n=44, ablation n=10, TACE+ablation n=27) prior to liver transplantation (LT) between 2010-2019. Immediate pre-LT cross-sectional imaging was used to assess modified Response Evaluation Criteria for Solid Tumors (mRECIST) response. Explant liver pathology was reviewed for percent (%) pathologic necrosis (PN). Associations between imaging and pathologic observations were statistically characterized using the Chi-squared and Kruskal-Wallis tests. RESULTS: Median time from imaging to LT was 37 (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 (SD). Mean %PN in CR tumors (89±21%) was significantly higher than PR (68±34%, P=0.005) and SD (67±36%, P=0.009). 60% (33/55) of CR tumors showed 100% complete PN (CPN) while only 20% (3/15) of PR and 18% (2/11) of SD showed CPN (P=0.002). There was no association between %PN or CPN across different LRT modalities and radiological response categories, indicating consistent performance between treatments. Sensitivity and specificity for radiologic CR to predict 100% PN was 87% and 49%. CONCLUSIONS: Radiologic-pathologic outcomes herein suggest that radiologic response criteria associate with PN, with no differences across treatment modalities. However, the imperfect predictive capacity of imaging for PN supports surveillance of treated tumors before LT.