Radioisotopic treatment of bone pain from metastatic prostate cancer

Hormone-refractory prostate cancer patients with painful bony metastatic lesions are potential candidates for bone-seeking radiopharmaceutical therapies. After careful assessment of symptoms and localization of pain, a bone scan is the single most useful imaging modality for the clinician to assess patients for the presence and distribution of osteoblastic lesions. Increased uptake (compatible with bony metastases) on a conventional bone scan is currently a prerequisite for treating patients with a bone-targeted therapeutic isotope. Determining whether metastatic bony involvement is focal or diffuse is also important in the clinical decision-making process. Patients with multifocal metastatic disease are excellent candidates for systemic therapies, whereas patients with unifocal metastatic disease may be more appropriate candidates for focal therapies such as external-beam radiation. Patients who are poorly tolerant of narcotics should be actively considered for alternative treatments such as systemic radiopharmaceuticals. Contraindications to administration of current bone-seeking radioisotopes include substantial degrees of renal insufficiency or bone marrow suppression.