Incidence of bone fracture in patients receiving luteinizing hormone-releasing hormone agonists for prostate cancer

Objective To investigate the incidence of bone fractures in patients receiv ing luteinizing hormone-releasing hormone agonists (LHRH-a) for prostate ca ncer (in whom a continued low testosterone level after the long-term admini stration of these drugs reduces bone mineral density), and thus determine t he risk of secondary osteoporosis. Patients and methods Between 1994 and 1999, 218 patients (mean age 77.3 yea rs) were treated for greater than or equal to 6 months with LHRH-a for pros tate cancer; of these, 14 (6%) had a bone fracture during their treatment. Patients with fracture associated with motor vehicle accidents were exclude d. The bone density in the third lumbar vertebra was meas-ured using quanti tative computed tomography. Osteocalcin, 1,25-(OH)(2) vitamin D, urinary ty pe 1 collagen cross-linked N-telopeptides (NTx), parathyroid hormone and ca lcitonin 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) mont hs. There was no case of a bone fracture at the site of a metastasis from p rostate cancer. The bone density was significantly lower in the patients wi th 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 metabol ic markers periodically, and to evaluate secondary osteoporosis in patients receiving long-term LHRH-a for prostate cancer.