title: Effect of re-irradiation for painful bone metastases on urinary markers of osteoclast activity (NCIC CTG SC.20U).
abstract: OBJECTIVE
  The NCIC CTG Symptom Control.20 randomized trial (SC.20) confirmed the effectiveness of re-irradiation to painful bone metastases. This companion study correlates urinary markers of osteoclast activity with response to re-irradiation, survival and skeletal related events (SREs).
  
  
  METHODS
  Pain response was assessed using the International Consensus Endpoints. Urinary markers of bone turnover-pyridinoline (PYD), deoxypyridinoline (DPD), N-telopeptide (NTX), Alpha and Beta cross-laps of C-telopeptide (CTX)-before and 1month after re-irradiation were correlated to response to re-irradiation and then to both, either or none of the initial and re-irradiation: frequent responders (response to both); eventual responders (response to re-irradiation only); eventual non-responders (response to initial radiation only), and absolute non-responders (no response to both).
  
  
  RESULTS
  Significant differences between 40 responders and 69 non-responders to re-irradiation existed for PYD (p=0.03) and DPD (p=0.04) at baseline. When patients were categorized as frequent responders (N=34), eventual responders (6), eventual non-responders (59) and absolute non-responders (10), the mean values of all markers in the absolute non-responders at baseline and the follow-up were about double those for the other three groups with statistically significant difference for DPD (p=0.03) at baseline. Absolute non-responders had the worst survival. The few occurrences of the SREs did not allow meaningful comparisons among the groups.
  
  
  CONCLUSIONS
  There were significant differences between responders and non-responders to re-irradiation for PYD and DPD at baseline. The urinary markers in the absolute non-responders were markedly elevated at both baseline and follow-up with a statistically significant difference for DPD at baseline.
authors.affiliation: Sunnybrook Odette Cancer Centre, University of Toronto, Canada. Electronic address: Edward.Chow@sunnybrook.ca.
authors.forename: Edward
authors.initials: E
authors.lastname: Chow
authors.affiliation: Sunnybrook Odette Cancer Centre, University of Toronto, Canada.
authors.forename: Carlo
authors.initials: C
authors.lastname: DeAngelis
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Kingston, Canada.
authors.forename: Bingshu E
authors.initials: BE
authors.lastname: Chen
authors.affiliation: Mount Sinai Hospital, University of Toronto, Canada.
authors.forename: Azar
authors.initials: A
authors.lastname: Azad
authors.affiliation: Juravinski Hospital and Cancer Centre and McMaster University, Hamilton, Canada.
authors.forename: Ralph M
authors.initials: RM
authors.lastname: Meyer
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Kingston, Canada.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Wilson
authors.affiliation: Tom Baker Cancer Centre, University of Calgary, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Kerba
authors.affiliation: Princess Margaret Hospital, Ontario Cancer Institute, University of Toronto, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bezjak
authors.affiliation: Bristol Haematology & Oncology Centre, UK.
authors.forename: Paula
authors.initials: P
authors.lastname: Wilson
authors.affiliation: Centre Hospitalier Universitaire de Sherbrooke, Canada.
authors.forename: Abdenour
authors.initials: A
authors.lastname: Nabid
authors.affiliation: Eastern Health, Division of Radiation Oncology, St. John's, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Greenland
authors.affiliation: Royal United Hospital, Bath, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Rees
authors.affiliation: Mount Sinai Hospital, University of Toronto, Canada.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Vieth
authors.affiliation: Princess Margaret Hospital, Ontario Cancer Institute, University of Toronto, Canada.
authors.forename: Rebecca K S
authors.initials: RK
authors.lastname: Wong
authors.affiliation: Mount Vernon Hospital Cancer Centre, Northwood, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Hoskin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000652:urine; D014408:Biomarkers, Tumor / Q000652:urine*; D001859:Bone Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D024042:Collagen Type I / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010010:Osteoclasts / Q000528:radiation effects*; D010455:Peptides / Q000652:urine
chemical_list: D000596:Amino Acids; D014408:Biomarkers, Tumor; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; C015484:pyridinoline; C036020:deoxypyridinoline
keywords: Bone metastases; Osteoclast activity; Re-irradiation; Urinary markers