Factors Associated With Complete Pathologic Necrosis of Hepatocellular Carcinoma on Explant Evaluation After Locoregional Therapy: A National Analysis Using the UNOS Database.

Abstract

<b>BACKGROUND.</b> Complete pathologic necrosis (CPN) is associated with improved survival in patients who undergo liver transplant (LT) after locoregional therapy (LRT) for hepatocellular carcinoma (HCC). <b>OBJECTIVE.</b> The purpose of this article was to identify patient, HCC, and transplant center characteristics associated with rates of CPN on explant evaluation using a large national sample of patients undergoing LT after LRT for HCC measuring 3 cm or smaller. <b>METHODS.</b> This retrospective study used data from the United Network for Organ Sharing database. The study included 6265 adults (median age, 62 years; 1505 women, 4760 men) who underwent LT after a single type of LRT (either transarterial chemoembolization [TACE], thermal ablation, or transarterial radioembolization [TARE]) for HCCs measuring 3 cm or smaller at one of 118 U.S. transplant centers from April 12, 2012, to March 31, 2020. Patients were classified as having CPN if explant evaluation showed 100% necrosis of all HCCs. Associations with CPN were explored. Centers were categorized into tertiles on the basis of center-level CPN rates, and tertiles were compared. <b>RESULTS.</b> LRT was performed by TACE in 69.5% (4352/6265), thermal ablation in 19.4% (1217/6265), and TARE in 11.1% (696/6265) of patients. CPN rate was 18.5% (805/4352) after TACE, 35.8% (436/1217) after thermal ablation, 33.6% (234/696) after TARE, and 23.5% (1475/6265) overall. In multivariable analysis incorporating age, sex, model for end-stage liver disease score, α-fetoprotein level before LRT, wait list time, number of HCCs, HCC size, and the transplant center (as a random factor), use of thermal ablation (OR, 2.19; 95% CI, 1.86-2.57; <i>p</i> < .001) or TARE (OR, 1.92; 95% CI, 1.57-2.36; <i>p</i> < .001), with TACE as reference, independently predicted greater likelihood of CPN. Center-level CPN rates ranged from 0.0% to 50.0%. With centers stratified by CPN rates, ablation was performed more frequently than TACE in 5.0% of centers in the first, 15.4% in the second, and 23.1% in the third tertiles (<i>p</i> = .07). <b>CONCLUSION.</b> CPN rate on explant evaluation was low. Thermal ablation or TARE, rather than TACE, was associated with higher likelihood of CPN in patient-level and center-level analyses. <b>CLINICAL IMPACT.</b> Findings from this large national sample support a potential role of thermal ablation or TARE for achieving CPN of HCC measuring 3 cm or smaller.