title: Selecting a comparison group for 5-year oral and pharyngeal cancer survivors: two methods.
abstract: BACKGROUND
  To assess potential long-term consequences of cancer treatment, studies that include comparison groups are needed. These comparison groups should be selected in a way that allows the subtle long-range effects of cancer therapy to be detected and distinguishes them from the effects of aging and other risk factors. The purpose of this investigation was to test two methods of recruiting a comparison group for 5-year oral and pharyngeal cancer survivors (peer-nominated and listed sample) with emphasis on feasibility and the quality of the match.
  
  
  METHODS
  Participants were drawn from a pool of 5-year survivors treated at a large Southeastern hospital. A peer-nominated sample was solicited from the survivors. A listed sample matched on sex, age, and zip code was purchased. Telephone interviews were conducted by a professional call center.
  
  
  RESULTS
  The following represent our key findings: The quality of matching between survivors and listed sample was better than that between survivors and peer-nominated group in age and sex. The quality of matching between the two methods on other key variables did not differ except for education, with the peer method providing a better match for the survivors than the listed sample. The yield for the listed sample method was greater than for the peer-nominated method. The cost per completed interview was greater for the peer-nominated method than the listed sample.
  
  
  CONCLUSIONS
  This study not only documents the methodological challenges in selecting a comparison group for studies examining the late effects of cancer treatment among older individuals but also documents challenges in matching groups that potentially have disproportionate levels of comorbidities and at-risk health behaviors.
authors.affiliation: Department of Community Dentistry and Behavioral Science, University of Florida, 1329 SW 16th Street Room 5174, Gainesville, FL 32610-3628, USA. hlogan@dental.ufl.edu
authors.forename: Henrietta L
authors.initials: HL
authors.lastname: Logan
authors.forename: Scott L
authors.initials: SL
authors.lastname: Tomar
authors.forename: Myron
authors.initials: M
authors.lastname: Chang
authors.forename: Glenn E
authors.initials: GE
authors.lastname: Turner
authors.forename: William M
authors.initials: WM
authors.lastname: Mendenhall
authors.forename: Charles E
authors.initials: CE
authors.lastname: Riggs
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D016022:Case-Control Studies; D005240:Feasibility Studies; D005260:Female; D005431:Florida; D015438:Health Behavior / Q000208:ethnology; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000453:epidemiology / Q000628:therapy*; D016011:Normal Distribution; D010043:Outcome and Process Assessment, Health Care / Q000191:economics / Q000379:methods* / Q000592:standards; D010147:Pain Measurement; D018579:Patient Selection; D010610:Pharyngeal Neoplasms / Q000453:epidemiology / Q000628:therapy*; D012307:Risk Factors; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology; D012923:Social Class; D015996:Survival Rate; D017741:Survivors / Q000523:psychology* / Q000706:statistics & numerical data