Reirradiation of Patients with Hepatocellular Carcinoma Is Associated with Decreased Liver Toxicity and Increased Survival
Abstract
Purpose
For a new course of liver stereotactic body radiation (reirradiation), we apply a normal tissue complication probability(NTCP) model to guide planning and estimate toxicity risk. We assessed the effectiveness of this approach in achieving longer survival and delaying liver toxicity in patients undergoing reirradiation for hepatocellular carcinoma(HCC), using retrospective matched patient data.
Methods
Time-to-event outcomes, including three-year survival(3yrS) and onset of liver toxicity, were analyzed for 290 patients without prior liver SBRT and 52 who received one previous SBRT course. In all reirradiation cases, patients were treated for a new hepatic lesion, not a previously irradiated tumor. For comparability, patients without prior irradiation were matched if their Albumin-Bilirubin(ALBI) values fell within the interquartile range(Q25–Q75) as seen in the reirradiation group. This matching yielded 107 patients without prior irradiation and 52 with reirradiation for direct comparison.
Results
Three-year survival was estimated using median restricted time estimators (MRTE): patients without prior irradiation had an MRTE of 24.3 months, while those with prior irradiation had 30.6 months, suggesting improved survival with reirradiation. For liver toxicity, defined by ALBI score increase ≥0.25, a similar matched cohort was analyzed. Time to liver toxicity MRTE was 14.3 months for patients without prior irradiation and 17.3 months for those with reirradiation, indicating delayed toxicity onset. Cox hazard analysis demonstrated lower risk of adverse outcomes in the reirradiation cohort, with a hazard ratio(HR) of 0.61 for survival(p < 0.01) and 0.70 for toxicity(p < 0.01), confirming significant benefit for reirradiated patients.
Conclusion
Reirradiation of the liver for new lesions, guided by an NTCP model, is linked to longer time to toxicity and improved three-year survival versus matched patients without prior hepatic irradiation. Favorable outcomes in the reirradiation group may reflect selection of patients with less aggressive disease or better liver function. Prospective studies are needed for confirmation and clarification.