Local control by salvage stereotactic body radiotherapy for recurrent/residual hepatocellular carcinoma after other local therapies.

To clarify local control by salvage stereotactic body radiotherapy (SBRT) for recurrent/residual hepatocellular carcinoma (HCC) compared with initial definitive SBRT for local treatment-naïve HCC. We retrospectively investigated HCC patients that received SBRT between July 2005 and December 2017. We classified HCC tumors as the initial definitive SBRT group (Arm-1; initial definitive SBRT, Arm-2; initial definitive planned SBRT following transarterial chemoembolization (TACE)) and salvage SBRT group (Arm-3; salvage SBRT for recurrent/residual tumors after TACE, Arm-4; salvage SBRT for recurrent/residual tumors after radiofrequency ablation (RFA), Arm-5; salvage SBRT for recurrent/residual other than Arm-3 or Arm-4). Local control was evaluated by mRECIST. We reviewed 389 HCC tumors of 323 patients treated by 35-40 Gy/5 fr. The median follow-up time for local recurrence of tumors was 34.8 months (range, 6.5-99.2). The cumulative local recurrence rates at 3 years of Arm-1-5 were 1.4% (95% CI, 0.3-4.4%), 5.0% (95% CI, 1.6-11.5%), 12.4% (95% CI, 5.7-21.9%), 14.8% (95% CI, 3.3-34.3%) and 7.3% (95% CI, 1.9-18.0%), respectively. The cumulative local recurrence rates at 3 years of initial definitive treatment and salvage treatment groups were 2.8% (95% CI, 1.1-5.6%) and 11.1% (95% CI, 6.3-17.3%), respectively (=.004). On multivariate analysis, salvage treatment and the tumor diameter were significant risk factors of local recurrence ( = .02,  < .001 respectively). Estimated overall survival at 3 years for all patients in initial definitive treatment and salvage treatment groups were 71.5% (95% CI, 63.4-78.1%) and 66.1% (95% CI, 56.4-74.2%), respectively ( = .20). No treatment-related death caused by SBRT was observed. This analysis showed local control of salvage SBRT for recurrent/residual HCC was significantly worse than that of initial definitive SBRT for local treatment-naïve HCC. However, local control of salvage SBRT was relatively good, and salvage SBRT is one of the favorable treatment options for recurrent/residual HCC.