Risedronate prevents bone loss in men receiving LHRH agonists
PHILADELPHIA—Prostate cancer patients treated with luteinizing hormone-releasing hormone (LHRH) have increased bone turnover and rapid bone loss within six months. A recent study suggests that this can be prevented with risedronate 35 mg once a week.
Historically, LHRH agonists were not used until men had metastatic disease, noted lead investigator Pamela Taxel, MD, assistant professor of medicine at the University of Connecticut Health Center in Farmington. Today, however, men with prostate cancer commonly are placed on these agents early in the course of their disease.
The double-blind, placebo-controlled, randomized trial of risedronate versus placebo was performed in 29 men (mean age 73 years) with locally advanced prostate cancer during the first six months of LHRH-agonist therapy. All men received 400 IU a day of an LHRH agonist and 600 mg of calcium a day. Thirteen men were assigned to receive risedronate 35 mg a week and 16 to placebo.
Dual energy x-ray absorptiometry was used to measure bone mineral density (BMD) at the lumbar spine (LS), femoral neck (FN), and total hip (TH) at baseline and at six months. Also measured were markers of bone resorption (N-telopeptide [NTX], and deoxypyridinoline [DPD]) and bone formation (bone specific alkaline phosphatase [BAP], and osteocalcin [OC]). At baseline, BMD and sex hormone and vitamin D levels did not differ between the groups, the study showed. The groups also had similar bone resorption and formation markers.
After six months, the risedronate group showed no change in femoral neck and total hip BMD compared with the placebo group. The latter group, however, had a 1.9% and 2.0% decrease in femoral neck and total hip BMD, respectively. In the risedronate group, LS BMD increased by 2.3% compared with the placebo group, which had no change. Urinary NTX decreased by 21% and OC decreased by 5% in the risedronate group, whereas NTX and OC increased by 21% and 55% in the placebo group.
Researchers reported study findings here at the 28th annual meeting of the American Society of Bone and Mineral Research.