International Patterns of Practice in Palliative Radiotherapy for Painful Bone Metastases: Evidence-Based Practice?

Abstract

To determine patterns of practice in palliative radiation therapy (RT) for painful bone metastases (BM) in view of randomized controlled trials and meta-analyses demonstrating the equivalence of single fraction (SF) and multi-fraction schedules. Radiation Oncologist members of the American Society of Therapeutic Radiology and Oncology (ASTRO), the Canadian Association of Radiation Oncology (CARO), and fellows of the Royal Australian and New Zealand College of Radiology (FRANZCR) were invited to participate. Respondents were asked to rate factors that influenced decision-making. Five case scenarios were presented; respondents were asked whether they would recommend RT, and if so, what dose and fractionation schedule. Descriptive statistics were compiled as proportions and medians (ranges), and two-sided Fisher's exact test was performed. A total of 962 eligible responses from 47 countries were received from respondents in practice a median of 14 years (range 1-49 years). A total of 49.1% were trained and 50.6% currently practice in the United States. 25.6% (185/722) of ASTRO respondents work in private practice, versus 13.9% (FRANZCR; p = 0.003) and 0% (CARO; p < 0.0001). Prognosis, spinal cord compression (SCC) and performance status were the top three factors taken into account by ASTRO and FRANZCR members; for CARO members, factors were SCC, evidence and prognosis. Median dose cited by ASTRO members was 30 Gy/10 for all cases (except re-treatment), compared to 8 Gy/1-20 Gy/5 for other respondents. For a solitary BM, on average 9.9% of ASTRO members would prescribe SF, compared to 29.6% (FRANZCR; p < 0.0001) and 33.8% (CARO; p < 0.0001). In the setting of neuropathic pain, 5.0% (33/654), 9.0% (9/100) and 16.5% (19/115) would use SF, respectively (p = 0.05 ASTRO vs. FRANZCR; p < 0.0001 ASTRO vs. CARO). Significantly fewer ASTRO respondents (25.7%) would use SF to retreat painful BM compared to 45.3% (FRANZCR; p = 0.0004) and 59.9% (CARO; p < 0.0001). Patients with painful bone metastases continue to be treated with multiple fraction schedules, especially by ASTRO members, despite multiple trials reporting the equivalence of SF. This suggests factors other than published evidence more strongly influence patterns of RT prescription. Multivariate analysis is underway to explore factors contributing to this variation in clinical practice.