3002 - MR-Guided Radiotherapy vs. Cone-Beam CT-Guided Radiotherapy for Hepatocellular Carcinoma: A Propensity-Matched Analysis

W. Jiang¹, X. Shi², X. Zhang¹, Z. Li², X. Xu³, L. Qi⁴, and J. Yue¹; ¹Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, ²Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, ³Department of Medical Administration, Shandong Cancer Hospital affiliated to Shandong First Medical University, Jinan, China, ⁴Department of Medical Equipment, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China

Purpose/Objective(s): The purpose of this study was to compare the efficacy and safety of MR-guided radiotherapy (MRgRT) with cone-beam CT-guided radiotherapy (CTgRT) in patients with hepatocellular carcinoma (HCC). Materials/

Methods: HCC patients staged I-III (American Joint Committee on Cancer stage, AJCC) treated with MRgRT or CTgRT at our institution from 2019 to 2023 were analyzed. Propensity score matching (PSM) was conducted to reduce selection bias between the two groups. Matching variables included age, sex, hepatitis B/C status, Eastern Cooperative Oncology Group performance status, alpha-fetoprotein status, albumin-bilirubin score, Child-Pugh class, AJCC stage, tumor number, largest tumor size, portal vein tumor thrombosis status, systemic treatment, and interventional treatment before radiotherapy. Overall survival (OS), in-field progression-free survival (IFPS), and radiation-induced liver disease (RILD) were evaluated in the pre- and post-PSM cohorts.
Results: A total of 122 patients (MRgRT: 51, CTgRT: 71) were included in this study. After PSM, 81 patients (MRgRT: 41, CTgRT 41) were matched. In the matched cohorts, the median OS was 28.8 months in the CTgRT group and was not reached in the MRgRT group. There was no significant difference in OS between the two groups. The 1-year IFPS rate of MRgRT was significantly better than that of CTgRT (91.9% vs. 65.2%, p = 0.0016). The mean biologically effective dose (BED) was higher in the MRgRT group (85.7 Gy vs. 67.6 Gy, p < 0.001). However, the risk of RILD in 3 months after radiotherapy was significantly lower in the MRgRT group (10.8% vs. 33.3%, p = 0.024).
Conclusion: MRgRT could deliver a higher radiation dose than CTgRT without increasing the risk of RILD and result in a better local control for those patients with HCC.