title: Evidence-based estimate of appropriate radiotherapy utilization rate for prostate cancer.
abstract: OBJECTIVE
  Current estimates of the proportion of cancer patients who will require radiotherapy (RT) are based almost entirely on expert opinion. The objective of this study was to use an evidence-based approach to estimate the proportion of incident cases of prostate cancer that should receive RT at any point in the evolution of the illness.
  
  
  METHODS
  A systematic review of the literature was undertaken to identify indications for RT for prostate cancer and to ascertain the level of evidence that supported each indication. An epidemiologic approach was then used to estimate the incidence of each indication for RT in a typical North American population of prostate cancer patients. The effect of sampling error on the estimated appropriate rate of RT was calculated mathematically, and the effect of systematic error using alternative sources of information was estimated by sensitivity analysis.
  
  
  RESULTS
  It was estimated that 61.2% +/- 5.6% of prostate cancer cases develop one or more indications for RT at some point in the course of the illness. The plausible range for this rate was 57.3%-69.8% on sensitivity analysis. Of all prostate cancer patients, 32.2% +/- 3.8% should receive RT in their initial treatment and 29.0% +/- 4.1% later for recurrence or progression. The proportion of cases that ever require RT is risk grouping dependent; 43.9% +/- 2.2% in low-risk disease, 68.7% +/- 3.5% in intermediate-risk disease; and 79.0% +/- 3.8% in high-risk locoregional disease. For metastatic disease, the predicted rate was 66.4% +/- 0.3%.
  
  
  CONCLUSIONS
  This method provides a rational starting point for the long-term planning of radiation services and for the audit of access to RT at the population level. By completing such evaluations in major cancer sites, it will be possible to estimate the appropriate RT rate for the cancer population as a whole.
authors.affiliation: Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Queen's University, Kingston Regional Cancer Centre and Kingston General Hospital, Kingston, Ontario, Canada.
authors.forename: Farshad
authors.initials: F
authors.lastname: Foroudi
authors.forename: Scott
authors.initials: S
authors.lastname: Tyldesley
authors.forename: Lisa
authors.initials: L
authors.lastname: Barbera
authors.forename: Jenny
authors.initials: J
authors.lastname: Huang
authors.forename: William J
authors.initials: WJ
authors.lastname: Mackillop
mesh_terms: D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011878:Radiotherapy / Q000706:statistics & numerical data*