The role of bisphosphonates in hormone-refractory prostate cancer

Men with advanced prostate cancer are at high risk for developing bone metastases, which result in clinically significant skeletal morbidity. Treatments that prevent skeletal complications in these patients could considerably improve their quality of life. Therefore, this paper reviews the role of bisphosphonates in the treatment of hormone-refractory prostate cancer (HRPC). Published studies were identified through MEDLINE searches, review of bibliographies of relevant articles, and review of abstracts from scientific meetings. Metastatic bone disease in men with HRPC results in skeletal complications such as pathologic fractures, spinal cord compression, and debilitating bone pain. First- and second-generation bisphosphonates, clodronate and pamidronate, had transient palliative effects that were not durable and did not prevent skeletal events in these patients. A small open-label study of ibandronate demonstrated significant reductions in pain, but these results have not been confirmed in a larger, randomized, controlled trial. To date, zoledronic acid is the only bisphosphonate that has demonstrated a statistically significant reduction in skeletal morbidity in this patient population. In a large, multicenter, randomized, placebo-controlled trial, treatment of men with HRPC and bone metastases with zoledronic acid significantly reduced skeletal-related events and provided a durable reduction of bone pain over 24 months compared with placebo. Zoledronic acid is the only bisphosphonate that has demonstrated efficacy for preventing skeletal complications in patients with HRPC and bone metastases. Therefore, initiation of zoledronic acid therapy should be considered to prevent skeletal morbidity and improve the quality of life of these patients.