A tandem colonoscopy study of adenoma miss rates during endoscopic training: a venture into uncharted territory

Background: Tandem colonoscopy is regarded as the reference standard for the evaluation of the adenoma detection rate (ADR) and adenoma miss rate (AMR) during colonoscopy. Pooled results from previous tandem studies yield AMRs of 22%. The AMR of trainees is important to estimate the number of colonoscopies required to develop competence in screening for colorectal neoplasms.

Objective: To measure the ADR and AMR of trainees as a function of experience.

Methods: Prospective tandem colonoscopy study at an academic VA medical center. A trainee initially attempted colonoscopy. If the trainee was able to intubate the cecum, the trainee performed the withdrawal, and the colonoscopy was then repeated by the attending physician to assess the AMR.

Results: Twelve trainee endoscopists were included in the study. Trainees had between 0 and 33 months of previous endoscopic experience and had done between 0 and 605 previous colonoscopies. A total of 230 patients were evaluated for the study, and 218 patients were enrolled. Complete tandem colonoscopy was performed in 147 patients. There was a 54% ADR. The mean (standard deviation) size of the adenomas in the cohort was 5.9 (5.3) mm. Significant variables in multivariate logistic regression analysis for missed adenomas were trainee experience (P = .011) and patient age (P < .001). The AMR decreased with increasing experience, and it is estimated that 450 colonoscopies are required to attain AMRs of less than 25% in a 60-year-old patient.

Limitations: Single-center study; the attending physician performing the second pass was not blinded to the first pass. The AMR was only analyzed for cases in which the trainee was able to reach the cecum with no or minimal assistance.

Conclusions: Our tandem colonoscopy study demonstrates that the AMR decreases as the experience of trainees increases and is a late competency attained during training. Future training may need to incorporate these findings to serve as a basis for determining appropriate training guidelines.