title: Are cancer-related decision aids effective? A systematic review and meta-analysis.
abstract: OBJECTIVE
  Decision aids (DAs) have been developed to improve communication between health professionals and patients, and to involve patients in decisions about their health care. Cancer-related decisions can be difficult due to problems in communicating complex information about prognosis and the modest benefits of available treatments. We conducted a systematic review of cancer-related DAs.
  
  
  METHODS
  Randomized controlled trials (RCTs) of cancer-related DAs about screening, prevention, and treatment decision making were included. We completed a comprehensive literature search and conducted both qualitative and quantitative analyses. We also conducted a meta regression to explore heterogeneity of effect estimates.
  
  
  RESULTS
  We identified 34 RCTs of DAs in a screening (n = 22 trials) or preventive/treatment (n = 12 trials) context. DAs significantly improved knowledge about screening options when compared to usual practice (weighted average effect size, 0.50; 95% CI, 0.27 to 0.73; P < .0001). A similar effect on knowledge was also found for preventive/treatment options (weighted average effect size, 0.50; 95% CI, 0.31 to 0.70; P < .0001). Overall, general anxiety was not increased in most trials and was significantly reduced in a screening context. Decisional conflict was reduced overall but not when screening and preventive/treatment studies were analyzed separately. There were few differences between different types of DAs.
  
  
  CONCLUSIONS
  Cancer-related DAs are effective in increasing patient knowledge compared with usual practice without increasing anxiety particularly in the area of cancer screening. Further research is needed to determine the effectiveness of DAs in the prevention and treatment context.
authors.affiliation: Supportive Cancer Care Research Unit, Juravinski Cancer Centre and McMaster University, 699 Concession St, Room 4-204, Hamilton, Ontario L8V 5C2, Canada. maobrien@mcmaster.ca
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: O'Brien
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Whelan
authors.forename: Miguel
authors.initials: M
authors.lastname: Villasis-Keever
authors.forename: Amiram
authors.initials: A
authors.lastname: Gafni
authors.forename: Cathy
authors.initials: C
authors.lastname: Charles
authors.forename: Robin
authors.initials: R
authors.lastname: Roberts
authors.forename: Susan
authors.initials: S
authors.lastname: Schiff
authors.forename: Wenjie
authors.initials: W
authors.lastname: Cai
mesh_terms: D003142:Communication; D003657:Decision Making; D003661:Decision Support Techniques; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D009369:Neoplasms / Q000175:diagnosis* / Q000517:prevention & control / Q000628:therapy*; D010358:Patient Participation; D010817:Physician-Patient Relations; D016032:Randomized Controlled Trials as Topic