Bone
pain from metastatic disease is most common in
cancers of the breast, prostate, and lung. Despite the World Health organization algorithm for treating such
pain, the outcomes are not often satisfactory. In 2005, there will be 3
radiopharmaceuticals available in the United States that can reduce or relieve bone
pain caused by osteoblastic
metastases with apparently equal efficacy.
Phosphorus-32 as
sodium phosphate,
strontium-89 ( 89Sr) as the
chloride, and
samarium-153 lexidronam may all be given intravenously (and 32P also orally) in patients where bone scintigraphy demonstrates a metastatic lesion causing the patient's bone
pain. Side effects are usually mild and include
pancytopenia with leukocyte and platelet nadirs at approximately 50% of baseline, and a mild-to-moderate, but brief, increase in
pain ("flare") in approximately 10% of patients. At least 1 of these radiotracers, 89Sr, has the availability to reduce the incidence of new bone
metastases as well, but, given alone, none prolong life. In a few studies in which 89Sr has been combined with
chemotherapy, prolongation of patient survival has been demonstrated. Many questions remain as to the optimization of use of this group of
radiopharmaceuticals, including whether combinations of
radiopharmaceuticals with each other, with
bisphosphonates or with
chemotherapy can improve the therapeutic outcomes even more.