The significance of ICG-R15 in predicting hepatic toxicity in patients receiving radiotherapy for hepatocellular carcinoma

Abstract

Purpose: The purpose of this study was to evaluate whether the retention rate of indocyanine green at 15 minutes following administration (ICGR15) could predict radiation-induced liver disease (RILD) in patients treated with radiotherapy (RT) for hepatocellular carcinoma (HCC).Methods and Materials: We retrospectively reviewed data from 146 HCC patients treated with RT between February, 1994 and December, 2008. The ICG-R15 was measured within 1 month prior to the start of RT. In this study RILD included both classic and nonclassic types. We analyzed the correlation between the incidence rate of RILD and the ICG-R15 before RT (pre-RT ICG-R15).Results: RILD occurred in 15 patients (10.3%); classic type in 5 patients (3.4%) and nonclassic RILD in 10 patients (6.9%). Univariate analysis indicated that cutoff value of pre-RT ICG-R15 could predict RILD significantly. The incidence of RILD for the patients with 22% or higher pre-RT ICG-R15 levels was 40.7% as compared to 3.4% for those with levels lower than 22% (p value<0.001). There was no clinical factor that significantly affected RILD on univariate analysis. Positive correlation was shown between the probability of RILD and increase in pre-RT ICGR15 (p<0.001).Conclusions: These results suggest that pre-RT ICG-R15 would be considered as one of the useful factors in predicting RILD in HCC patients treated with RT. A greater than 22% of pre-RT ICG-R15 level is significantly correlated with RILD following RT in HCC patients. Therefore, the pre-RT ICG-R15 level could serve as a RT indication parameter in the RT guidelines for HCC.