Comparison of pain response and functional interference outcomes between spinal and non-spinal bone metastases treated with palliative radiotherapy

Purpose The purpose of this study was to compare functional interference and pain response outcomes using the Brief Pain Inventory (BPI) for patients treated with palliative radiotherapy to spine versus non-spine bones and determine if dose fractionation was associated with each group's respective response. Materials and methods Patients treated for painful bone metastases with palliative radiotherapy during May 2003 to June 2007 were analyzed. The BPI was utilized at baseline and monthly for 6 months post-radiation. Pain response was determined using International Bone Metastases Consensus response definitions. Wilcoxon rank-sum test (for continuous variable), Fisher exact test (for categorical value), and two-way analysis of variance were used for comparisons, and a p value of <= 0.05 was considered statistically significant. Results Three hundred eighty-six patients were analyzed, 62% were treated with a single fraction, 38% with multiple fractions. Pain and functional interference scores significantly improved over time in both spine and non-spine sites. At 3 months, 42% of all patients had a partial response, and 25% had a complete response. Location of bone metastases and radiotherapy dose were not predictive factors for pain response nor functional interference following radiation treatment. Conclusion Spine and non-spine bone metastases exhibited similar pain and functional interference improvements over a period of 6 months post-radiotherapy. There were, however, high attrition rates as expected with palliative studies, with approximately half the patients remaining in this study by 3 months and a fifth by 6 months. A single 8 Gy resulted in equal benefits in terms of both pain response and improvement in function.