Modelling XXXX detection in ulcerative colitis: clinical implications of surveillance intensity.

@entity75 @entity1960 @entity14 @entity6349 @entity1141
BACKGROUND: Endoscopic surveillance of @entity1960 uses random biopsies to find @entity6349 fields. Enhanced endoscopic methods are more sensitive for @entity1141 detection, but their specificity for @entity14 risk is unknown. AIMS: To develop a mathematical model of the sensitivity of random biopsy surveillance, and determine the implications of negative, a single positive, or multiple positive biopsies for @entity1141 , and compare the detection threshold to that detectable by enhanced endoscopy. METHODS: Using mathematical modelling, we calculated the confidence level with which @entity1141 can be excluded, the @entity6349 field size detection threshold, the predicted area of a @entity6349 field, and the number of biopsies needed for a given @entity1141 detection threshold and confidence level. RESULTS: 32 random biopsies provide only 80% confidence that @entity1141 involving > or =5% of the colon can be detected. When a single biopsy of 18 is @entity6349 , this predicts a @entity6349 area (89 cm(2)) several orders of magnitude greater than @entity6349 fields that are readily detectable by enhanced endoscopy (1 cm diameter), and the predicted field size increases rapidly with multiple positive biopsies. CONCLUSIONS: Random biopsy surveillance is sufficiently sensitive to detect large @entity6349 fields with significant @entity14 risk. Enhanced endoscopy can detect much smaller @entity6349 fields, but these have unknown (perhaps much lower) @entity14 risk. Small @entity6349 fields should not be assumed to indicate a high @entity14 risk that warrants colectomy. Prospective studies are needed to define the @entity14 risk and optimal management of small @entity75 .
