Dose escalation using helical tomotherapy improves local control in spine metastases from primary hepatic malignancies

Background & AimsThis study was designed to reveal the prognostic significance of dose-escalated radiotherapy with tomotherapy in local control for spine metastases of primary hepatic tumours. MethodsFrom April 2006 to May 2012, 23 hepatocellular carcinoma patients and 7 intrahepatic cholangiocellular carcinoma patients (total 30 patients, 42 spinal lesions) were treated for metastatic spine lesions with helical tomotherapy (HT). The gross tumour volume (GTV) was defined as a tumour evident from computed tomography and magnetic resonance imaging. Median values were as follows: GTV total dose of 48Gy (range 21-51), fraction size of 6Gy (range 3-8) and eight fractions (range 3-17). Pain response was checked according to visual analogue scale (from 0 to 10). ResultsThe median follow-up was 5.6months. Six events of local failure occurred, including five lesions in which spinal canals were involved at radiotherapy. Local control rate at 3months was 86.6%. Biological equivalent dose (BED) was correlated with local control (AUC=0.833). Higher BED (>56.0Gy(10)) was associated with increased local control (P=0.004). The median time to local progression in patients receiving 56.0Gy(10) and >56.0Gy(10) were 3 and 20.8months respectively. Dose escalation (BED>56.0Gy(10)) was also associated with improved progression-free survival (median 14.7 vs. 2.8months, P=0.010). Pain reduction was observed in 90.9% (20/22) of patients with painful bone metastases. ConclusionsDose-escalated radiotherapy (BED>56.0Gy(10)) using HT improved local control in spinal metastases of hepatic malignancies.