title: Change in urinary markers of osteoclast activity following palliative radiotherapy for bone metastases.
abstract: OBJECTIVE
  To examine the effect of radiotherapy for bone metastases on urinary markers of osteoclast activity.
  
  
  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 8 Gy or 20 Gy 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<0.01). From our study population, 58 (64%) were classified as responders and 57 (46%) as non-responders to radiotherapy. We compared the urinary markers between the responders and the non-responders. There were no statistically significant differences between the two groups either in terms of baseline markers or in terms of month 1 follow-up markers. There was no significant change from baseline to the 1 month follow-up in responders or in non-responders to radiotherapy.
  
  
  CONCLUSIONS
  Baseline levels of urinary markers could not predict which patient would benefit from palliative radiotherapy.
authors.affiliation: Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Chow
authors.forename: A
authors.initials: A
authors.lastname: Hird
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.forename: E
authors.initials: E
authors.lastname: Sinclair
authors.forename: C
authors.initials: C
authors.lastname: Danjoux
authors.forename: E
authors.initials: E
authors.lastname: Barnes
authors.forename: M
authors.initials: M
authors.lastname: Tsao
authors.forename: L
authors.initials: L
authors.lastname: Barbera
authors.forename: Shun
authors.initials: S
authors.lastname: Wong
authors.forename: R
authors.initials: R
authors.lastname: Vieth
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000652:urine*; D001859:Bone Neoplasms / Q000532:radiotherapy* / Q000556:secondary / Q000652:urine; D018450:Disease Progression; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008297:Male; D008875:Middle Aged; D010010:Osteoclasts / Q000528:radiation effects*; D010146:Pain / Q000517:prevention & control / Q000532:radiotherapy* / Q000652:urine; D010147:Pain Measurement; D010166:Palliative Care; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects*
chemical_list: D015415:Biomarkers