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.