*Purpose: As a bridge to liver transplantation, locoregional treatments are commonly employed in hepatocellular carcinoma (HCC) patients to prevent tumor progression during waiting time. Objective of our study was to evaluate the rate of complete pathologic response in patients undergoing locoregional bridging treatment, to analyze the effect of complete pathologic response on post-transplant recurrence, and identify factors that predict the ability to achieve complete pathologic response after undergoing locoregional bridging treatment.

*Methods: We performed a retrospective review of all adult patients who underwent liver transplantation for HCC between January 2007 and December 2017 in our transplant center. Locoregional bridging therapies included radiofrequency ablation, TACE, radioembolization or a combination of the above. The type and number of treatment as well as the time from last treatment to liver transplantation was recorded.

*Results: On explant specimen, complete pathologic tumor necrosis was achieved in 35.4% of patients while 64.6% of patients achieved partial or no tumor necrosis. There were no differences regarding age, gender, underlying liver disease, MELD score and Milan criteria in patients with complete tumor necrosis compared to patients without. Patients with treatment response had significantly smaller (28 [12-175] vs. 36 [12-225] mm, p 0.0023) and less tumor nodules (>3 nodules in 20.7% vs. 37.4%, p 0.0278). Pre-treatment AFP was lower in the complete response group, however, this did not reach statistical significance (14.1 [1.1-43611.0] vs. 28.0 [1.1-538184.0] IU/ml, p 0.0760). On explant specimen, poor differentiation (1.6% vs. 21.7%, p 0.0003) and microvascular invasion (0.0% vs. 20.0%, p 0.0001) was significantly less frequently present in the complete response group. In the entire cohort, 16.3% of patients developed recurrent HCC. Tumor recurrence was significantly less frequent among patients with complete treatment response (3.2% vs. 23.5%, p 0.0005). Multivariate analysis detected tumor size and numbers as well as poor differentiation being individually associated with decreased odds of treatment response.

*Conclusions: Successful bridging treatment leading to complete necrosis may facilitate successful liver transplantation in HCC patients. Treatment response is less likely achieved in tumors of large numbers or size and poor differentiation.

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