Objective To investigate the incidence of bone fractures in patients receiving luteinizing hormone-releasing hormone agonists (LHRH-a) for prostate cancer (in whom a continued low testosterone level after the long-term administration of these drugs reduces bone mineral density), and thus determine the risk of secondary osteoporosis.
Patients and methods Between 1994 and 1999, 218 patients (mean age 77.3 years) were treated for 6 months with LHRH-a for prostate cancer; of these, 14 (6%) had a bone fracture during their treatment. Patients with fracture associated with motor vehicle accidents were excluded. The bone density in the third lumbar vertebra was meas-ured using quantitative computed tomography. Osteocalcin, 1,25-(OH)2 vitamin D, urinary type 1 collagen cross-linked N-telopeptides (NTx), parathyroid hormone and calcitonin were measured as metabolic markers.
Results The mean age of the patients with fracture was 78 years; the mean (range) interval from the start of treatment to fracture was 28 (11–46) months. There was no case of a bone fracture at the site of a metastasis from prostate cancer. The bone density was significantly lower in the patients with a fracture than in those without. Of the bone metabolic markers, NTx was higher in those with a fracture.
Conclusion There is a need to measure bone mineral density and bone metabolic markers periodically, and to evaluate secondary osteoporosis in patients receiving long-term LHRH-a for prostate cancer.