Single fraction external beam radiation therapy in the treatment of localized metastatic bone pain. A review.

Bone metastases are a frequent complication of cancer, and frequently cause pain. Indications for radiotherapy for bone metastases include pain, risk for pathologic fracture, and neurological complications arising from spinal cord compression, nerve root pain or cranial nerve involvement. There are numerous fractionation patterns of external beam radiation therapy for painful bone metastasis, both fractionated schedules and single fraction regimens. All prospective randomized trials that evaluated differences in the outcomes associated with various fractionated regimens versus single fraction regimens unequivocally showed that single fraction regimens (mostly 8 Gy) are at least equal with various fractionated regimens. The single fraction regimens have an additional advantage of being more convenient to both patients and hospitals. However, there are still numerous questions that are left unanswered in these trials, such as the "optimal" single fraction that should be used, the possibility for retreatment, and prognostic factors that may help identify those patients more likely to respond to a single fraction radiation therapy in the treatment of painful bone metastasis.