# Stereotactic Body Radiation Therapy for Intrahepatic Graft Recurrences of Hepatocellular Carcinoma After Liver Transplantation: A Report of Two Cases

## TL;DR

This paper reports on the successful use of stereotactic body radiation therapy to treat liver cancer recurrences after liver transplants in two patients.

## Contribution

The paper presents the first reported cases of SBRT used for post-transplant intrahepatic hepatocellular carcinoma recurrences.

## Key findings

- SBRT achieved 100% local control in all treated lesions in both patients.
- No SBRT-related adverse events were observed, and liver function was maintained.
- Progression occurred outside the treated areas, suggesting the need for combined therapies.

## Abstract

The management of intrahepatic recurrences after orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC) is challenging. Graft hepatectomy may not be feasible, and systemic therapy (ST) options are limited due to the increased risk of graft rejection with immunotherapy use. Stereotactic body radiation therapy (SBRT) is a safe and effective locoregional therapy (LRT) option for HCC, although there is a paucity of data in the post-OLT setting. Here, we present two cases of post-OLT intrahepatic HCC recurrences treated with SBRT.

Two patients who received SBRT for post-OLT intrahepatic recurrences were identified from a single academic institution with a high-volume liver transplant program. Prior to treatment, cases were reviewed at a multidisciplinary liver tumor board. Baseline and treatment characteristics, as well as clinical outcomes such as local control (LC), progression-free survival (PFS), and adverse events (AEs), were retrospectively evaluated from the date of SBRT completion to last follow-up. Linear accelerator-based liver SBRT was planned using four-dimensional computed tomography (4DCT) simulation, abdominal compression, and volumetric modulated arc therapy. Institutional planning objectives were followed to achieve PTV95%>99% and to limit liver Dmean <18 Gy and D700cc <15 Gy.

Patient 1 (P1) and patient 2 (P2) underwent OLT for hepatitis C virus-associated HCC. The SBRT indication was for synchronous intrahepatic and oligometastatic progression without prior LRT (P1) and metachronous intrahepatic progression after five courses of non-SBRT LRT (P2). Time from OLT to SBRT was 6.7 years (P1) and 23.2 years (P2). Post-SBRT follow-up time was 20.9 months (P1) and 18.1 months (P2). Liver SBRT dose was 35 Gy in five fractions. P1 received synchronous SBRT to oligometastases involving the right adrenal gland and right lung. Intrahepatic PTV volumes were 230 cc (P1) and 114 cc (P2). For all treated lesions (n=5), LC was 100%. PFS was 9.7 months (P1) and 10.4 months (P2), with out-of-field intrahepatic progression being the only site of progression in both patients. No SBRT-related AEs were identified, and Child Pugh A status was maintained over the follow-up period. Neither patient received ST prior to SBRT; however, due to progression, P1 was started on first-line levanetinib 13 months after SBRT completion.

SBRT was effective and well tolerated in the treatment of two patients with intrahepatic HCC recurrences following OLT for HCC. Individualized treatment approaches incorporating SBRT for intrahepatic and extrahepatic recurrences should be considered in this population. Further analyses are warranted to compare the safety and efficacy of SBRT to other LRT options and in combination with ST in this patient population.