Radiation therapy has a major role in the palliation of localized symptomatic metastases,  Indications for external-beam radiation therapy include the following:  Painful bony metastases.  Unresectable central nervous system metastases (i.e., brain, meninges, and spinal cord).  Bronchial obstruction.  Fungating/painful breast or chest wall lesions.  After surgery for decompression of intracranial or spinal cord metastases.  After fixation of pathologic fractures.  Strontium chloride Sr 89, a systemically administered radionuclide, can be administered for palliation of diffuse bony metastases.

Source:  NCI  2019