Maintaining Bone Strength in Men With Prostate Cancer

The purpose of this study is to see if giving zoledronic acid three times a year is as effective as five times a year, in increasing bone strength in men with prostate cancer. All participants will receive the active drug but half will receive drug every 6 months and the other half will receive drug every 3 months. Both patient and doctor will know which treatment a patient is receiving. After 1 year of treatment bone strength will be measured with scans and compared to the strength at the start of the study. All participants will stop receiving the drug after 1 year and will be seen back in the clinic, annually for another 2 years for follow-up.