Scientific Abstracts: Liver
Objective: Immune factors and inflammation play a key role for disease progression in hepatocellular carcinoma (HCC). With chemoembolization (DEB-TACE) as a bridge to liver transplant, this study evaluates the role of these factors in posttransplant recurrence and lymphovascular invasion of the treated tumors.
Methods: A grant-funded, retrospective, case-control explant analysis was performed on 17 patients who were treated for HCC with DEB-TACE (100-300µ LC Beads™ mixed with doxorubicin) and bridged to liver transplant from 6/2012 to 9/2015. 5 cases of posttransplant recurrence were selected from a previously published consecutive cohort of 93 patients who were bridged to transplant with TACE (Sandow et al. Assessing Response to DEB-TACE: Tumor Biology and HCC Recurrence in a 5-year transplant cohort. Radiology 2018; 286(3):1072-1083.). The cases of posttransplant recurrence were matched to similar cases based on tumor count, size, and treatment response. The explanted tumor specimens were pulled from catalog, identified as the tumors treated with TACE, and retrospectively evaluated for PD-L1 and CD-8 expression. Specimens were evaluated by 2 board-certified pathologists at separate institutions.
Results: Prior to transplant, complete response (CR) was present in 6 patients (35%), partial response (PR) in 1 patient (6%), stable disease in 8 patients (47%), and disease progression in 2 patients (12%). At explant, PD-L1 expression was high in 10 patients (59%), and peri-tumoral CD-8 expression was high in 4 patients (24%). On the basis of recurrence, patients were appropriately matched based on treatment size (p=0.34), tumor count (p=0.17), and treatment response (p=0.61). However, high PD-L1 expression was significantly associated with posttransplant recurrence (5/5 [100%] with recurrence vs 5/12 [42%] without recurrence, p=0.01). Additionally, high peri-tumoral CD-8 expression was associated with posttransplant recurrence (3/5 [60%] with recurrence vs 1/12 [8%] without recurrence, p=0.03) as well as lymphovascular invasion (3/6 [50%] vs 1/11 [9%], p=0.06). CR prior to transplant was associated with lower rates of high PD-L1 expression at explant (2/6 [33%] with CR vs 8/11 [73%] with PR/SD/DP, p=0.11).
Conclusions: Tumor-mediated immune tolerance may play a role in posttransplant recurrence in patients who were bridged to liver transplant with TACE.