The effect of combined intravenous and oral clodronate treatment on bone pain in patients with metastatic prostate cancer.

: Although osteosclerotic metastases are characteristic of prostate cancer, bone resorption is also accelerated. Clodronate is a specific inhibitor of osteoclastic bone resorption and relieves bone pain of osteolytic lesions in myelomatosis and breast cancer. The present open study included 16 prostate cancer patients who had painful bone metastases and who had failed hormonal therapy. Clodronate was given intravenously for six days (300 mg/day) followed by oral treatment for 21 days (3200 mg/day). A clear pain relief was found in nine of the 16 (56%) patients after intravenous administration. During the next three weeks with oral administration there was still pain reduction in five patients, while in three patients the pain increased. The treatment had no effect on conventional tumour markers but urinary hydroxyproline excretion decreased, indicating reduced bone resorption. Clodronate offers an alternative for treating patients with painful metastases from prostate cancer.