Dose-fractionation schedules for radiotherapy of bone metastases

Background: Bone metastases are common in breast cancer patients. Radiotherapy is safe and effective. This review aimes to contribute to the definition of the appropriate radiation regimens for different endpoints. Material and Methods: Information was compiled by searching PubMed and MEDLINE databases including early-release publications. When possible, primary sources were quoted. Full articles were obtained. References were checked for additional material when appropriate. Results: Randomized trials and meta-analyses demonstrated that single-fraction radiotherapy with 1 × 8 Gy is as effective for pain relief as multi-fraction regimens such as 5 × 4 Gy or 10 × 3 Gy. Re-irradiation for recurrent pain is required more often after single-fraction radiotherapy. Re-irradiation with another single fraction is safe and effective. Multi-fraction long-course radiotherapy such as 10 × 3 Gy leads to better re-calcification and better local control of metastatic spinal cord compression (MSCC). Because both re-calcification and MSCC recurrences occur only several months after radiotherapy, long-course radiotherapy is particularly appropriate for patients with a favorable survival prognosis. Conclusions: For uncomplicated painful bone metastases, single-fraction radiotherapy with 1 × 8 Gy may be considered the standard regimen. If re-calcification is a major goal, longer-course radiotherapy (i.e. 10 × 3 Gy) should be used. For MSCC, 10 × 3 Gy is preferable for patients with a favorable survival prognosis.