Targeted and systemic radiotherapy in the treatment of bone metastasis.

Cancer metastasis to the bone develops commonly in patients with a variety of malignancies, and is a major cause of morbidity and diminished quality of life in a significant proportion of cancer patients. The effective treatment of bone metastasis requires cooperation between medical, surgical and radiation oncologists. Radiotherapy, either in the form of targeted external beam radiation therapy, or systemic administration of radionuclides, plays a central role in treatment of symptomatic bone metastases. The appropriate external beam treatment techniques, dose and fractionation regimens for the treatment of symptomatic, localized bone metastasis have been established in prospective clinical trials. Large-field, hemi-body irradiation has been utilized for treatment of symptoms related to more widely disseminated bone metastases, but has been associated with substantial toxicity. Strontium-89 and Samarium-153 are widely available systemically administered radionuclides that are useful for the treatment of widely disseminated disease, and have largely supplanted the use of hemi-body irradiation. Combined with appropriate medical and surgical interventions, as well as the appropriate use of analgesics, radiotherapy is a well-tolerated and highly effective treatment for the palliation of symptomatic bone metastases.