Randomized controlled trial of zoledronic acid to prevent bone loss in men receiving androgen deprivation therapy for nonmetastatic prostate cancer

Purpose: A multicenter double-blind, randomized, placebo controlled clinical trial was performed to assess the effect of zoledronic acid, a potent new bisphosphonate, on bone mineral density during androgen deprivation therapy for non-metastatic prostate cancer. Materials and Methods: Men with MO (no distant metastases) prostate cancer beginning androgen deprivation therapy were randomly assigned to receive 4 mg. zoledronic acid or placebo intravenously every 3 months for I year. The primary efficacy variable was the percent change from baseline to I year in bone mineral density of the lumbar spine as measured by dual energy x-ray absorptiometry. Results: A total of 106 men were enrolled in the trial. Mean bone mineral density in the lumbar spine increased by 5.6% in men receiving zoledronic acid and decreased by 2.2% in those given placebo (mean difference 7.8%, 95% confidence interval 5.6%-10.0%, p < 0.001). Mean bone mineral density of the femoral neck, trochanter and total hip also increased in the zoledronic acid group and decreased in the placebo group. Zoledronic acid was well tolerated. Conclusions: Zoledronic acid increases bone mineral density in the hip and spine during androgen deprivation therapy for nonmetastatic prostate cancer.