Bone scintigraphy following intravenous pamidronate for Paget's disease of bone.

Pamidronate is one of several powerful bisphosphonates able to produce prolonged remissions of Paget's disease. This study examined to what extent bone scan changes parallel the clinical response and whether there is variability in the behavior of individual lesions. Twenty-five patients with pagetic bone pain for more than 2 yr were examined with bone scintigraphy before and on average 8 mo after six 30-mg infusions of pamidronate given weekly. Serum alkaline phosphatase and urinary hydroxyproline-to-creatinine ratios were measured before and 6 mo after treatment. A second course of pamidronate was given to 13 patients who had clinical or biochemical relapse. Of 136 pagetic lesions, 13 (10%) completely resolved, 90 (65%) improved and 33 (24%) remained unchanged. There was no significant difference in response between bony sites, although less active lesions were more likely to resolve completely. In conclusion pamidronate has a powerful effect on bone scan appearances in Paget's disease. Most lesions improve but complete resolution is uncommon. Less active lesions are more likely to resolve and are less likely to require further therapy.