Current status of systemic intravenous radiopharmaceuticals for the treatment of painful metastatic bone disease.

PURPOSE

Intractable bone pain secondary to bone metastasis from prostate, lung, breast, and other malignancies is a major problem in the management of the oncological patient. Because a number of factors are implicated in the pathophysiology of bone pain, a multidisciplinary approach in its assessment and treatment is often required. Treatment often includes the use of analgesic drug therapy; however, radiation therapy, hormonal therapy, chemotherapy, and surgery may also be needed.

METHODS AND MATERIALS

The use of systemic radionuclide therapy may often be helpful to relieve bone pain and improve the quality of life. In the setting of diffuse bone metastasis, intractable to conventional therapy, various radioisotopes have been advocated. These include phosphorous-32, iodine-131, strontium-89, yttrium-90, samarium-153, and rhenium-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 responses seen in 60-80% of patients, depending on the extent of disease and stage the patient is treated. Retreatment has been possible in certain cases with further palliation being offered and improvement in the various quality of life parameters being noted.

CONCLUSION

Myelotoxicity has been a limiting factor with certain isotopes and has led to the development of less toxic bone seeking agents. Although these each have unique physical and biokinetic properties requiring different doses and protocols for administration, they all appear to localize in osteoblastic metastatic sites in sufficient amounts to provide bone pain palliation.