OCCURRENCE AND CLINICAL-SIGNIFICANCE OF OVERT BLOOD-LOSS PER RECTUM IN THE GENERAL-POPULATION AND IN MEDICAL-PRACTICE

While the occurrence of blood loss per rectum in general practice is c ommon and usually not serious, it may be the first symptom of a colore ctal malignant disorder. To determine the occurrence and clinical sign ificance of overt blood loss per rectum a Medline literature search wa s undertaken. The incidence of this symptom in the general population was reported to be approximately 20 per 100 people per year, the 'cons ultation incidence' in general practice approximately six per 1000 and the incidence of referral to a medical specialist was estimated to be about seven per 10 000 per year. The clinical significance of the sym ptom varied within different populations: the predictive value of over t rectal blood loss for colorectal malignancy was estimated to be less than one in 1000 in the general population, approximately two in 100 in general practice and up to 36 in 100 in referred patients. How the manifestation of the bleeding (and other signs and symptoms) contribut es to the selection of patients at each of these stages, leading to in creasing prior probabilities, is unknown.