title: The value of reasons for encounter in early detection of colorectal cancer.
abstract: BACKGROUND
  Symptoms with a high predictive power for colorectal cancer (CRC) do not exist.
  
  
  OBJECTIVE
  To explore the predictive value of patients' reason for encounter (RFE) in the two years prior to the diagnosis of CRC.
  
  
  METHODS
  A retrospective nested case-control study using prospectively collected data from electronic records in general practice over 20 years. Matching was done based on age (within two years), gender and practice. The positive likelihood ratios (LR+) and odds ratios (OR) were calculated for RFE between cases and controls in the two years before the index date.
  
  
  RESULTS
  We identified 184 CRC cases and matched 366 controls. Six RFEs had significant LR + and ORs for CRC, which may have high predictive power. These RFEs are part of four chapters in the International Classification of Primary Care (ICPC) that include tiredness (significant at 3-6 months prior to the diagnosis; LR+ 2.6 and OR 3.07; and from 0 to 3 months prior to the diagnosis; LR+ 2.0 and OR 2.36), anaemia (significant at three months before diagnosis; LR+ 9.8 and OR 16.54), abdominal pain, rectal bleeding and constipation (significant at 3-6 months before diagnosis; LR+ 3.0 and OR 3.33; 3 months prior to the diagnosis LR+ 8.0 and OR 18.10) and weight loss (significant at three months before diagnosis; LR+ 14.9 and OR 14.53).
  
  
  CONCLUSIONS
  Data capture and organization in ICPC permits study of the predictive value of RFE for CRC in primary care.
authors.affiliation: a Department of Primary and Community Care , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands ;
authors.forename: Susan J M
authors.initials: SJ
authors.lastname: van Boxtel-Wilms
authors.affiliation: a Department of Primary and Community Care , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands ;
authors.forename: Kees
authors.initials: K
authors.lastname: van Boven
authors.affiliation: a Department of Primary and Community Care , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands ;
authors.forename: J H Hans
authors.initials: JH
authors.lastname: Bor
authors.affiliation: a Department of Primary and Community Care , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands ;
authors.forename: J Carel
authors.initials: JC
authors.lastname: Bakx
authors.affiliation: a Department of Primary and Community Care , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands ;
authors.forename: Peter
authors.initials: P
authors.lastname: Lucassen
authors.affiliation: b Formerly of the Department of General Practice , Academic Medical Centre, University of Amsterdam , Amsterdam , the Netherlands ;
authors.forename: Sibo
authors.initials: S
authors.lastname: Oskam
authors.affiliation: a Department of Primary and Community Care , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands ;|c Department of Primary and Community Care , Radboud University Medical Centre, Nijmegen, The Netherlands ;|d Australian Primary Health Care Research Institute , Australian National University , Canberra , Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: van Weel
mesh_terms: D015746:Abdominal Pain / Q000453:epidemiology / Q000209:etiology*; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003248:Constipation / Q000453:epidemiology / Q000209:etiology; D055088:Early Detection of Cancer; D057286:Electronic Health Records; D005221:Fatigue / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D058006:General Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013997:Time Factors; D015431:Weight Loss
keywords: Reason for encounter; colorectal cancer; diagnosis; primary care