Change in urinary markers of osteoclast activity following palliative radiotherapy for bone metastases.

Abstract Aims To examine the effect of radiotherapy for bone metastases on urinary markers of osteoclast activity. Materials and methods Patients with radiological evidence of bone metastases planned for palliative radiotherapy were eligible for the study. A urine specimen was collected before and 1 month after radiotherapy to assess levels of calcium, creatinine, magnesium, phosphate, N-telopeptide and pyridinoline. The Brief Pain Inventory was completed in person at baseline and by telephone follow-up at 1 month after radiotherapy. Patients were classified as responders (complete or partial pain response) or non-responders (stable or progressive pain) to radiotherapy based on the International Bone Metastases Consensus Criteria for end point measurements. Absolute values of urine markers were compared between responders and non-responders, or between responders and patients with progression. Results Our study population consisted of 74 men and 51 women. A single 8Gy or 20Gy in five daily fractions were commonly employed. At the 1 month follow-up, all Brief Pain Inventory functional interference scores showed a highly significant decrease from baseline ( P Conclusion Baseline levels of urinary markers could not predict which patient would benefit from palliative radiotherapy.