General principles of external beam radiation therapy for skeletal metastases.

Radiation therapy plays a major role in the treatment of patients with bone metastases. The primary goals of treatment include pain relief and relief of neurologic symptoms, if present. Approximately 70% of patients will achieve pain relief with palliative external beam radiotherapy. Improvement in the severity of pain may occur within as few as 48 to 72 hours of initiation of therapy, but in some patients significant relief of pain may not occur for 4 weeks after completion of therapy. Treatment schemes ranging from 800 cGy in a single treatment to 3000 cGy in 10 treatments have not been shown to result in major differences in outcome. Treatment decisions must be individualized based on factors such as the patient's performance status, life expectancy, location of the lesion, and size of area to be treated. External beam radiotherapy is recommended after surgical treatment of pathologic fractures or impending fractures to decrease the need for a second surgical procedure and improve the patient's functional outcome. External beam radiotherapy continues to be an important component of the palliative treatment of bone metastases. Its integration with newer therapeutic modalities such as vertebroplasty and radiofrequency ablation currently is being studied.