Background: The insertion of a colonoscope to the caecum is a difficult technique to teach and to learn. The most commonly used criterion for proficiency is completion rate and early experience is often discouraging. In order to document the learning curve and better define normal progress for the early learning experience, the performance of trainees during their first 100-125 cases was recorded.
Methods: The completion rate and time for office colonoscopy were recorded prospectively over a 5-year period for each of 18 trainees. Trainees' experience was analysed in groups of 25 cases, numbered chronologically. Completion rate was defined as the number of examinations completed to the caecum by the trainee expressed as a percentage of the number completed by the staff.
Results: The mean overall completion rate for trainees was 56.4% (range 27.8-83.9%). For the first five groups of 25 cases, the percentage completion rates (in order from first 25 cases to fifth 25 cases) were 43.1, 52.6, 49.3, 61.8 and 75.1%, respectively. There was a wide variation in completion rates between trainees, but no difference in time taken. (Time for trainees to complete the procedure, in order from the first 25 cases to fifth 25 cases: 18.7, 19.1, 19.4, 17.6 and 17.1 min, respectively.)
Conclusions: Early experience in colonoscopy can be discouraging. At least 100 cases are needed to attain a level of proficiency that enables completion in two-thirds of cases, whereas 125 cases lead to an average completion rate of 75%.