title: Fractionation of Palliative Radiation Therapy for Bone Metastases in Ontario: Do Practice Guidelines Guide Practice?
abstract: OBJECTIVE
  To evaluate the effect of a provincial practice guideline on the fractionation of palliative radiation therapy for bone metastases (PRT.B) in Ontario.
  
  
  METHODS
  The present retrospective study used electronic treatment records linked to Ontario's population-based cancer registry. Hierarchical multivariable regression analysis was used to evaluate temporal trends in the use of single fractions (SFs), controlling for patient-related factors associated with the use of SFs.
  
  
  RESULTS
  From 1984 to 2012, 43.9% of 161,835 courses of PRT.B were administered as SFs. The percentage of SF courses was greater for older patients (age <50 years, 39.8% vs age >80 years, 52.5%), those with a shorter life expectancy (survival >12 months, 36.9% vs < 1 month, 53.6%), and those who lived farther from a radiation therapy center (<10 km, 42.1% vs > 50 km, 47.3%). The percentage of SFs to spinal fields was lower than that to other skeletal sites (31.5% vs 57.1%). The percentage of SFs varied among the cancer centers (range, 26.0%-67.8%). These differences were all highly significant in the multivariable analysis (P<.0001). In 2004, Cancer Care Ontario released a practice guideline endorsing the use of SFs for uncomplicated bone metastases. The rate of use of SFs increased from 42.3% in the pre-guideline period (1999-2003) to 52.6% in the immediate post-guideline period (2004-2007). However, it subsequently decreased again to 44.0% (2009-2012). These temporal trends were significant after controlling for patient-related factors in the multivariable analysis (P<.0001). Large intercenter variations in the use of SFs persisted after publication of the guideline.
  
  
  CONCLUSIONS
  The publication of an Ontario practice guideline endorsing the use of SF PRT.B was associated with only a transient increase in the use of SFs in Ontario and did little to reduce intercenter variations in fractionation.
authors.affiliation: Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Queen's University, Kingston, Ontario, Canada; Cancer Center of Southeastern Ontario, Kingston, Ontario, Canada.
authors.forename: Allison
authors.initials: A
authors.lastname: Ashworth
authors.affiliation: Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Queen's University, Kingston, Ontario, Canada.
authors.forename: Weidong
authors.initials: W
authors.lastname: Kong
authors.affiliation: Sunnybrook Regional Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Edward
authors.initials: E
authors.lastname: Chow
authors.affiliation: Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Queen's University, Kingston, Ontario, Canada; Cancer Center of Southeastern Ontario, Kingston, Ontario, Canada. Electronic address: william.mackillop@krcc.on.ca.
authors.forename: William J
authors.initials: WJ
authors.lastname: Mackillop
mesh_terms: D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000532:radiotherapy* / Q000556:secondary*; D002173:Cancer Care Facilities / Q000706:statistics & numerical data; D019583:Dose Fractionation, Radiation; D006297:Health Services Accessibility; D006801:Humans; D008017:Life Expectancy; D008875:Middle Aged; D009864:Ontario; D010146:Pain / Q000532:radiotherapy; D010166:Palliative Care / Q000592:standards*; D017410:Practice Guidelines as Topic; D012044:Regression Analysis; D012189:Retrospective Studies; D017678:Sex Distribution