Maintaining bone health in patients with prostate cancer

Loss of bone mineral density with androgen deprivation therapy (ADT) for prostate cancer is well recognised, with significant loss of bone mineral density (BMD) occurring within 12 months of starting therapy. With ADT, annual loss of BMD is about 2%-8% per year at the lumbar spine and 1.8%-6.5% at the hip; the loss appears to continue indefinitely while treatment continues, and there is no recovery after therapy is ceased. 19.4% of men surviving at least 5 years after diagnosis of prostate cancer have a fracture if treated with ADT compared with 12.6% of men not receiving ADT; this is equivalent to one additional fracture for every 28 men treated with ADT. Vitamin D deficiency exacerbates the development of osteoporosis, so vitamin D status should be evaluated before commencing ADT in men with prostate cancer. Treatment with bisphosphonates (zoledronate, pamidronate and alendronate) in men treated with ADT have been shown to prevent bone loss in prospective studies and to increase BMD in one randomised controlled trial; bisphosphonates have not been shown to prevent fractures in men with prostate cancer. Further prospective trials are required to assess the efficacy and cost-effectiveness of bisphosphonates in men with prostate cancer who require treatment with ADT. All doctors need to take an active role in monitoring bone health in patients with prostate cancer requiring ADT.