To compare a single fraction of 8 Gy with a course of multifraction radiotherapy in terms of long-term benefits and short-term side effects in patients with painful skeletal metastases.

Seven hundred and sixty-five patients with painful skeletal metastases requiring palliative radiotherapy were entered into a prospective randomised clinical trial comparing 8 Gy single fraction with a multifraction regimen (20 Gy/5 fractions or 30 Gy/10 fractions). Patients recorded pain severity and analgesic requirements on self-assessment questionnaires before treatment, at 2 weeks and at 1, 2, 3, 4, 5, 6, 8, 10 and 12 months after radiotherapy. Pain relief was the primary endpoint of treatment benefit. Short-term side-effects were compared in a subset of 133 consecutive patients who graded nausea, vomiting and antiemetic usage prior to treatment and at daily intervals from days I to 14.

Overall survival at 12 months was 44%, with no statistically significant difference apparent between randomised groups. There were no differences in the time to first improvement in pain, time to complete pain relief or in time to first increase in pain at any time up to 12 months from randomisation, nor in the class of analgesic used. Retreatment was twice as common after 8 Gy than after multifraction radiotherapy, although retreatment for residual or recurrent pain did not reflect a difference between randomised groups in the probability of pain relief. The difference in the rate of retreatment is thought to reflect a greater readiness to prescribe radiotherapy after a single fraction, not a greater need. There were no significant differences in the incidence of nausea, vomiting, spinal cord compression or pathological fracture between the two groups.

A single fraction of 8 Gy is as safe and effective as a multifraction regimen for the palliation of metastatic bone pain for at least 12 months. The greater convenience and lower cost make 8 Gy single fraction the treatment of choice for the majority of patients.