Impact of zoledronic acid (Z) on pain in prostate cancer patients with bone metastases in a randomised placebo-control trial

4638 Background: Bone metastases occur in up to 80% of advanced prostate cancer patients and can results in painful Skeletal-Related Events (SREs). Z is the only biphosphonate approved for metastatic prostate cancer that decreases the occurrence of SREs which include pathologic fractures, severe bone pain requiring radiation therapy, spinal cord compression, surgery to bone and hypercalcemia of malignancy which may lead to daily activity limitations. We performed retrospective analyses on data from a placebo-controlled study of Z to investigate which items of the Brief Pain Inventory (BPI) were most sensitive to changes in patient’s pain due to treatment. Methods: Prostate cancer patients with bone metastases received Zoledronate 4 mg (n = 201) or placebo (n = 201). The BPI was administered at baseline (visit 2), and visits 3 (weeks 3–4), 4 (weeks 6–8), and then every second visit (every 6 weeks) until study end. Changes in BPI individual item scores and the Pain Severity and Pain Interference scale score...