Background: Many randomized trials in the treatment of bone metastases have reported that radiotherapy reduces bone pain and decreases analgesic consumption. However, reporting of other pain-related functional outcomes has been sparse. The primary objective of this study was to prospectively determine changes in pain intensity and its functional interference following palliative radiotherapy for painful bone metastases.

Materials and Methods: Patients with symptomatic bone metastases treated with palliative radiotherapy from May 2003 to June 2005 were followed with the Brief Pain Inventory (BPI) at baseline, 1, 2, and 3 months after the delivery of radiotherapy. Radiotherapy outcome was assessed using the International Bone Metastases Consensus response definitions.

Results: One hundred and ninety-nine patients were treated with palliative radiotherapy. All three pain scores and seven functional interference items at two months showed a significant improvement compared to the baseline. Complete, partial and overall response rates of the 101 patients who completed the BPI assessment at two months were 21%, 45% and 66%, respectively.

Conclusions: External beam radiation therapy was found to be effective in palliating pain from bone metastases and reducing pain-related functional interference. Incorporating functional interference outcomes in future clinical trials may improve the assessment of meaningful treatment effect.