Impact of Tumor Size on Patients With Hepatocellular Carcinoma Treated With Stereotactic Ablative Radiotherapy.

Abstract

Background/aim: Stereotactic ablative radiotherapy (SABR) can deliver tumoricidal doses to hepatocellular carcinoma (HCC). To date, there is a paucity of research reporting the impact of maximal tumor diameter (MTD) on patients with HCC treated with SABR.

Patients and methods: The medical records of patients with HCC with Barcelona Clinic Liver Cancer (BCLC) stage A to C diseases treated with linear accelerator-based SABR between 2015 and 2021 were reviewed. Overall survival (OS), in-field progression-free survival (IFPFS), out-field progression-free survival (OFPFS), and distant metastasis-free survival (DMFS) were calculated using Kaplan-Meier analysis. The Cox regression model was performed to examine the effects of variables.

Results: This retrospective study included 62 patients. The median MTD and measured tumor volume were 5.3 cm (range=1.7-10 cm) and 41 ml (range=3.2-454 ml), respectively. Thirty-one patients (50%) had vascular invasion. Patients received a median prescribed dose of 48 Gy (30-54 Gy) in five to six fractions. Over a median follow-up of 19 months (range=4-66 months), six, 36, and 25 patients experienced in-field failure, out-field hepatic recurrence, and extrahepatic metastases, respectively. The estimated 2-year OS and IFPFS rates were 45.9% and 90.6%, respectively. In the univariate analysis, MTD over 5.3 cm was associated with inferior OS. In the multivariate analysis, MTD or other clinical parameters failed to influence any clinical endpoints. A total of nine patients (14.5%) developed radiation-induced liver disease.

Conclusion: A MTD up to 10 cm did not significantly impact in-field progression following SABR. Although the prescribed dose of 48 Gy in five to six fractions can achieve superior in-field control, most treatment failures were due to out-field relapse.