Editorial: Interval cancers after colonoscopy: the importance of training.

This study by Singh et al. adds to the emerging story of colorectal cancers diagnosed after colonoscopy. In a retrospective analysis of a large Canadian registry, 7.9% of all cancers had a colonoscopy performed between 6 and 36 months before the diagnosis, likely representing cancers that were missed at the prior colonoscopy. The rate varied by location and gender of the patient, with a maximum of 14.4% of cancers located in the transverse colon or splenic flexure among women having been missed at a prior colonoscopy. The evidence presented in this study supports a deficit in colonoscopy quality rather than accelerated tumor biology as the cause of the majority of interval cancers. Moreover, endoscopist specialty remained a significant predictor of missed cancers despite adjustment for procedural volume, indicating that even non-gastroenterologists who handle a high volume of procedures continue to miss more cancers than gastroenterologists. These results highlight the need for more stringent standards for training and assessment of competence to perform colonoscopic screening for colorectal neoplasia.