Background
Phase III RCT (RTOG 97-14). 898 patients with painful bone metastases from breast or prostate cancer. Randomized to 8 Gy in 1 fraction vs 30 Gy in 10 fractions. Largest North American trial comparing single-fraction to multi-fraction palliative RT for bone metastases. Aimed to determine if single fraction is equivalent to multi-fraction for pain palliation.
Interventions and follow up
Arm A: 8 Gy × 1 fraction to painful bone metastasis site
Arm B: 30 Gy × 10 fractions (3 Gy/fx) to painful bone metastasis site
Primary endpoint: Pain response at 3 month
mFollow up: 24 month
Arm B: 30 Gy × 10 fractions (3 Gy/fx) to painful bone metastasis site
Primary endpoint: Pain response at 3 month
mFollow up: 24 month
Results
Complete + partial pain response (8 Gy): 66% vs 30 Gy 68%, P=.6 — equivalent
Complete pain response: 15% (8 Gy) vs 18% (30 Gy), P=.6
Re-treatment rate: 18% (8 Gy) vs 9% (30 Gy), P<.001
Pathologic fracture: 5% (8 Gy) vs 4% (30 Gy), P=.6
Complete pain response: 15% (8 Gy) vs 18% (30 Gy), P=.6
Re-treatment rate: 18% (8 Gy) vs 9% (30 Gy), P<.001
Pathologic fracture: 5% (8 Gy) vs 4% (30 Gy), P=.6
Adverse events
Main adverse events: Acute toxicity (8 Gy): grade ≥2 less frequent — diarrhea 3% vs 5%, nausea 10% vs 16%. Pain flare 24 hours post-RT: higher with single fraction (14% vs 6%). Corticosteroid prophylaxis recommended for pain flare prevention.
Conclusions
Single-fraction 8 Gy achieves equivalent pain palliation to 30 Gy/10 fractions for bone metastases from breast and prostate cancer with less acute toxicity. The higher re-treatment rate with single fraction (18% vs 9%) is an important consideration, particularly for patients with longer expected survival.
Key Limitations
Key Limitations: Pain flare higher with single fraction — prophylactic dexamethasone recommended. Higher re-treatment rate requires longer-lived patients to make multiple clinic visits. Does not address pathologically complex sites (weight-bearing, impending fracture) where multi-fraction may be preferable. Limited to breast and prostate cancers.
Clinical Context
RTOG 97-14 (with the Dutch Bone Pain Study and UK BPII) established single-fraction 8 Gy as equivalent to 30 Gy/10 fractions for uncomplicated bone metastases. Single fraction is preferred in patients with limited prognosis and multiple sites requiring treatment. ASTRO, ESMO, and NCCN guidelines support single-fraction as the standard for uncomplicated painful bone metastases.
References