Frequency of Zoledronic Acid to Prevent Further Bone Loss in Osteoporotic Patients Requiring Androgen Deprivation Therapy for Prostate Cancer

Androgen Deprivation Therapy is the mainstay of treatment for advanced prostate cancer. However they are associated with accelerated bone loss, osteoporosis and fractures. Previous studied looking at the use of zoledronic acid have predominantly studied men with a normal or osteopenic bone mineral density. However, it has been shown that upto 40% of men presenting with prostate cancer have osteoporosis and it is these who are at most risk of osteoporotic fractures. Our aim was to evaluate the efficiency of zoledronic acid in 2 groups of osteoporotic patients, those undergoing treatment with LHRH agonists and with antiandrogens.Peripheral and axial bone densitometry will be used to measure percentage changes in bone mineral density over 3 years. The first year with the patients on LHRH or antiandrogen, the second year continuing with their androgen deprivation therapy and zoledronic acid. Then bone mineral density will be measured one year following the last infusion of zoledronic acid to ascertain the optimum frequency of administration.

The study will also involve monitoring serum and urine bone turnover markers.