Efficacy and safety of 3D-conformal half body irradiation in patients with multiple bone metastases

Half-body irradiation (HBI) represented a standard treatment for multiple painful bone metastases (BMs). However, its use has progressively reduced due to the associated toxicity rates. The aim of this paper was to evaluate HBI delivered by conformal radiotherapy (RT) technique in a large patients population with widespread BMs. HBI was delivered in 3 Gy fractions, bid, ≥ 6 h apart, on 2 consecutive days (total dose: 12 Gy) using 3-dimensional conformal RT (3D-CRT) box technique. The target included pelvic bones, lumbar-sacral vertebrae and upper third of femurs. Acute and late toxicity was scored based on RTOG and EORTC-RTOG scales, respectively. Pain was evaluated using the Pain-Drug scores and the Visual Analog Scale (VAS). One hundred and eighty patients were eligible for inclusion in this retrospective analysis. Grade 3 and 4 acute toxicity rates were 1.1% and 0.0%, respectively. Mean VAS before and after HBI was 5.3 versus 2.7, respectively (p: 0.0001). Based on VAS, 37.5% of patients showed complete pain relief (VAS: 0) while 38.1% had partial response (≥ 2-point VAS reduction). Overall, Pain and Drug Score reduction was observed in 76.3% and 50.4% of patients, respectively. 1-, 2-, and 3-year pain progression free survival was 77.0%, 63.4%, and 52.7%, respectively. Thirty patients (16.7%) underwent RT retreatment on the same site with median 15.9 months interval (range 2-126 months). HBI delivered with 3D-CRT technique is safe and effective. It provides long lasting pain control in patients with multiple BMs with negligible rates of relevant toxicity.