Zoledronic acid to prevent skeletal complications in cancer: corroborating the evidence

Bone metastases are a major cause of cancer morbidity. Bone metastases are associated with pain, fractures, spinal cord compression, ineffective haematopoiesis, and hypocalcaemia of malignancy. The goals of treatment for bone metastases are to prevent disease-related skeletal complications, palliate pain, and maintain quality of life. Bisphosphonates are a standard part of supportive care for patients with bone metastases. Zoledronic acid, a nitrogen containing third generation bisphosphonate, is the most active and is the most thoroughly investigated bisphosphonate for metastatic bone disease. The efficacy and safety of zoledronic acid has been established in three pivotal prospective, randomized controlled trials involving more than 3000 subjects. The evidence is reviewed here with a focus on clinical relevance. Across a broad array of tumour types, zoledronic acid (4 mg intravenously over 15 min every 3-4 weeks) decreased the frequency of skeletal-related events, delayed the time to a first skeletal-related event, and reduced pain. Zoledronic acid is more effective than pamidronate in breast cancer and the only bisphosphonate proven effective for metastatic prostate cancer, lung cancer, renal cell carcinoma and other solid tumours.