Background
ASTRO Evidence-Based Clinical Practice Guideline on Palliative Radiotherapy for Bone Metastases. Systematic review and guideline development process. Addresses dose/fractionation for uncomplicated painful bone metastases, re-irradiation, SBRT/SABR for spinal metastases, and role of radionuclide therapy. Published 2017 (update of 2011 guideline) based on pooled analysis of randomized trials.
Interventions and follow up
Arm A: N/A — guideline/consensus document
Primary endpoint: Level of evidence for each recommendatio
mFollow up: N/A
Primary endpoint: Level of evidence for each recommendatio
mFollow up: N/A
Results
Key recommendations: Multiple fractionation schedules; SBRT for oligometastatic spine; radiopharmaceuticals for diffuse bone metastases
Single fraction (8 Gy): Equivalent to multi-fraction for uncomplicated bone pain — GRADE A recommendation
SBRT for spine: GRADE B — superior local control vs conventional RT; appropriate for radioresistant histologies
Re-irradiation: GRADE B — 8 Gy × 1 or 20 Gy × 5 appropriate for recurrent bone pain
Radionuclides (strontium, samarium): GRADE B — appropriate for diffuse painful bone metastases from prostate/breast cancer
Single fraction (8 Gy): Equivalent to multi-fraction for uncomplicated bone pain — GRADE A recommendation
SBRT for spine: GRADE B — superior local control vs conventional RT; appropriate for radioresistant histologies
Re-irradiation: GRADE B — 8 Gy × 1 or 20 Gy × 5 appropriate for recurrent bone pain
Radionuclides (strontium, samarium): GRADE B — appropriate for diffuse painful bone metastases from prostate/breast cancer
Adverse events
Main adverse events: Pain flare: 10–40% after single fraction — prophylactic dexamethasone 8 mg × 3 days recommended. SBRT: vertebral compression fracture 10–40% (dose and vertebral involvement dependent). Radionuclides: myelosuppression, bone marrow concern before chemotherapy.
Conclusions
Multiple dose/fractionation schedules are effective for bone pain palliation. Single-fraction 8 Gy is recommended as the standard for uncomplicated bone metastases given equivalent efficacy and patient convenience. SBRT is recommended for spine metastases where long-term control is needed. Re-irradiation is feasible and effective.
Key Limitations
Key Limitations: Evidence base relies largely on pain response endpoint, not patient-reported functional outcomes or survival. Optimal RT technique for complex sites (acetabulum, femoral neck) is less well-defined. SBRT for non-spinal bone metastases has limited randomized data.
Clinical Context
The ASTRO Bone Metastases guideline is the foundational reference for palliative RT practice. Single-fraction 8 Gy is the standard for uncomplicated bone metastases at most academic and community centers. SBRT to spine is increasingly offered for oligometastatic disease, radioresistant histologies, and prior RT sites.
References