CURRENT STATUS OF SYSTEMIC INTRAVENOUS RADIOPHARMACEUTICALS FOR THE TREATMENT OF PAINFUL METASTATIC BONE-DISEASE

Purpose: Intractable bone pain secondary to bone metastasis from prost ate, lung, breast, and other malignancies is a major problem in the ma nagement of the oncological patient. Because a number of factors are i mplicated in the pathophysiology of bone pain, a multidisciplinary app roach in its assessment and treatment is often required. Treatment oft en includes the use of analgesic drug therapy; however, radiation ther apy, hormonal therapy, chemotherapy, and surgery may also be needed. M ethods and Materials: The use of systemic radionuclide therapy may oft en be helpful to relieve bone pain and improve the quality of life. In the setting of diffuse bone metastasis, intractable to conventional t herapy, various radioisotopes have been advocated. These include phosp horous-32, iodine-131, strontium-89, yttrium-9O, samarium-153, and rhe nium-186, often as either the anionic phosphate or as a ligand (HEDP, EDTMP). Results: When these agents are used, pain relief often occurs in approximately 2-4 weeks and lasts several weeks to months with resp onses seen in 60-80% of patients, depending on the extent of disease a nd stage the patient is treated. Retreatment has been possible in cert ain cases with further palliation being offered and improvement in the various quality of life parameters being noted.Conclusion: Myelotoxic ity has been a limiting factor with certain isotopes and has led to th e development of less toxic bone seeking agents. Although these each h ave unique physical and biokinetic properties requiring different dose s and protocols for administration, they all appear to localize in ost eoblastic metastatic sites in sufficient amounts to provide bone pain palliation.