Stereotactic Radiation Therapy for Post-Transplant Systemic Recurrence of Hepatocellular Carcinoma: Safety, Efficacy and a Nomogram Predicting Overall Survival

Jingru Chen¹Gengmin Niu¹Xin Guo²Yuxuan Tao¹Xiaobin Liu³Yan Xie⁴Li Zhang⁴Wentao Jiang⁴Zhiyong Yuan^1*Zhongqiu Wang^1*

• ¹Department of Radiation Oncology, CyberKnife Center, Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
• ²Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital of Chinese Academy of Medical Sciences, Langfang, China
• ³Department of Radiology, Tianjin Medical Imaging Institute, Tianjin First Central Hospital, School of Medicine, Nankai University, Tianjin, China
• ⁴Department of Liver Transplantation, Tianjin First Center Hospital, NHC Key Laboratory for Critical Care Medicine, Key Laboratory of Transplantation, Chinese Academy of Medical Sciences, Tianjin, China

Background: Stereotactic Radiation Therapy (SRT) has proven effective for various stages of Hepatocellular Carcinoma (HCC), however, its role in managing intra-or extrahepatic recurrence after liver transplantation remains underexplored. Objectives: This study evaluates the safety and efficacy of SRT delivered using the CyberKnife® system for recurrent HCC after liver transplantation and introduces a novel nomogram for predicting survival to guide individualized management. Methods: In a single-center retrospective study conducted between 2007 and 2020, 79 patients with recurrent HCC after transplantation presenting 133 intra-or extrahepatic lesions were treated with SRT. Treatment response, survival outcomes, and local control rates were evaluated. Multivariate analysis identified significant prognostic factors, which were incorporated into a predictive nomogram for survival. Results: With a median follow-up of 11.4 months, median overall survival (OS) was 15.1 months, and the local control rate was 90.5%. The OS rates at 6 months, 1 year, and 2 years were 78.9%, 57.1%, and 38.9%, respectively. Key factors associated with improved survival included fewer than three lesions, AFP <500 ng/ml, KPS ≥70, and total gross tumor volume (GTV) <40 mL. The nomogram demonstrated good predictive accuracy with a validated C-index of 0.760. Treatment was well tolerated, with no severe treatment-related toxicities observed. Conclusion: SRT provides effective local control for both intra-and extrahepatic recurrences of HCC after liver transplantation. The proposed nomogram offers a valuable tool for personalized surveillance and treatment planning.