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General Practice

Rectal bleeding and colorectal cancer in general practice: diagnostic study

BMJ 2000; 321 doi: (Published 21 October 2000) Cite this as: BMJ 2000;321:998
  1. Hans Wauters, general practitionera,
  2. Viviane Van Casteren, epidemiologistb,
  3. Frank Buntinx (, professorb
  1. a Department of General Practice, Catholic University of Leuven, 3000 Leuven, Belgium
  2. b Department of Epidemiology, Scientific Institute of Public Health, B 1050, Brussels
  1. Correspondence to: F Buntinx
  • Accepted 12 May 2000

Although most cases of rectal bleeding are due to local conditions, this symptom is a major sign of colorectal cancer. Little research exists on whether to refer a patient with rectal bleeding for further evaluation.1-3 We therefore studied the diagnostic value of rectal bleeding in relation to a subsequent diagnosis of colorectal cancer.

Subjects, methods, and results

In Belgium, a network of sentinel practices, covering 1% of the population, registers epidemiological data.4 The methods used to estimate the denominator (in patient years) have been published.4

We analysed data on all patients with colorectal cancer diagnosed in 1993–4 to evaluate sensitivity (retrospective study). We chose rectal bleeding as the reason for visiting a general practitioner before colorectal cancer was diagnosed as the main outcome measure.

To obtain a positive predictive value (prospective part of study), we included all patients presenting with rectal bleeding in 1993-4. Our reference standard was colorectal cancer diagnosed …

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