Optimal timing of radiotherapy for incomplete transarterial chemoembolization in BCLC stage B hepatocellular carcinoma.

Abstract

521 Background: Numerous studies have reported on the efficacy of radiotherapy (RT) after incomplete transarterial chemoembolization (TACE). However, the optimal timing of RT remains unclear. This study investigated the optimal time of initiating RT for incomplete TACE in patients with BCLC stage B hepatocellular carcinoma (BCLC-B HCC). Methods: Between 2001 and 2016, 116 lesions in 104 patients with BCLC-B HCC were treated with RT after TACE. The time interval between the last session of TACE and initiation of RT was obtained from medical records and analyzed retrospectively. The optimal cut-off time-interval that maximized the difference in local failure-free rate (LFFR) was determined using maximally selected rank statistics. Results: The median duration between TACE and RT was 26 (range: 2–165) days. Median number of TACE treatments on the target lesion before RT was 2; median tumor size was 7 cm. At a median follow-up of 18 (range: 3–160) months, the median overall survival was 18 months. The probability of local control increased as the time interval between TACE and RT decreased. The optimal cut-off value of the time interval was 5 weeks. With the cut-off of 5 weeks, 65 and 39 patients were classified into early and late RT groups, respectively. The early RT group had significantly poorer Child-Pugh class and higher alpha-fetoprotein levels. Most characteristics including tumor size (7 cm vs. 6 cm; P = .144) were not significantly different between the groups. One-year LFFR was significantly higher in the early RT group (94.6% vs. 70.8%; P = .005). On multivariate analysis, early RT was an independent predictor of favorable LFFR (hazard ratio: 3.82, 95% confidence interval: 1.64–8.88, P = .002). Conclusions: The optimal time for the administration of RT for incomplete TACE is within 5 weeks following TACE. Early administration of RT within 5 weeks after TACE was associated with better local control.