OC-0191: IAEA randomised trial of optimal single dose radiotherapy in the treatment of painful bone metastases

Background To determine the optimal single-dose radiotherapy schedule for pain from bone metastases in a multi-centre, international, randomised trial. Patients and methods 651 patients were randomised to either 8Gy (n=325) or 4Gy (n=326) radiotherapy. Pain at 4, 8, 12, 24 and 52weeks was assessed using a Categorical Scale (CS) and a Visual Analogue Scale (VAS). The primary endpoint was response at 4weeks. Results There was no significant difference in patient demographics and other co-variates. The complete response (CR) rate and ORR (complete or partial response) for all follow-up times were higher after 8Gy (p=0.02). The Kaplan–Meier actuarial rate (categorical scale) at 4weeks for ORR was 80% after 8Gy compared to 68% after 4Gy (p=0.0015). 117 re-treatments were given of which 72 were in the 4Gy group and 45 in 8Gy arm (p=0.01). Conclusions There was a marked consistent difference in pain relief at all time points in favour of 8Gy. These data reinforce the case for single dose 8Gy radiotherapy to be recommended for metastatic bone pain in all healthcare settings.