The influence of timing of colonoscopy on adenoma detection: is timing everything?

Colorectal cancer is a common disease in the United States. The majority of sporadic colorectal cancers develop from adenomatous polyps. In the United States, the incidence of colorectal cancer is declining, most likely because of colonoscopic polypectomy. Adenoma detection rate is affected by the quality of prep, careful mucosal inspection, and withdrawal time. In this issue of the Journal, there is intriguing evidence that the timing of colonoscopy, morning vs. afternoon, affects adenoma detection rate. Physician fatigue is postulated as a factor leading to lower polyp detection rates in the afternoon compared with the morning. Further, prospective studies are needed to confirm these findings and determine the effect on clinical practice.