Delay in progression of bone metastases in breast cancer patients treated with intravenous pamidronate: results from a multinational randomized controlled trial. The Aredia Multinational Cooperative Group.

PURPOSE: Bone metastases are a major cause of morbidity in breast cancer, resulting in complications that include pain, loss of mobility, pathologic fracture, and tumor-induced hypercalcemia (TIH). Inhibition of osteoclast-mediated bone destruction using bisphosphonates represents a promising new management approach. PATIENTS AND METHODS: Breast cancer patients with bone metastases were randomly allocated to receive chemotherapy alone (152 patients) or chemotherapy plus pamidronate 45 mg in 250 mL of saline as a 1-hour intravenous infusion every 3 weeks (143 patients). Whenever possible, treatment continued until progression of disease (PD) in bone appeared on radiographs or bone scan. Time to PD in bone and pain reduction according to a self-assessment six-point scale were selected as primary end points. PD in bone was verified during extramural review (EMR) of all imaging studies by blinded observers, and these data were used as the main efficacy criterion. Analgesic intake, World Health Organization (WHO) performance status, and complications of bone metastases (radiotherapy, TIH, fractures, orthopedic surgery) were also compared in the two groups. RESULTS AND CONCLUSION: At EMR, median time to PD in bone was increased by 48% in patients who received pamidronate (249 v 168 days; P = .02, Wilcoxon test). Marked pain relief, defined as a two-point decrease lasting for > or = 6 weeks, was reported by 44% of pamidronate patients and by 30% of controls (P = .025, chi 2 test). The infusions (median, nine per patient; range, 0 to 39) were well tolerated, with no major toxicities reported. Pamidronate by repeated infusion can significantly slow the progression of bone metastases and reduce attendant morbidity.