Endoscopist specialty is associated with incident colorectal cancer after a negative colonoscopy

The incidence of colorectal cancer (CRC) is reduced for at least 10 years after a negative colonoscopy, compared with the general population. However, CRCs do occur in individuals after a negative colonoscopy. We investigated whether the colonoscopy volume and specialty of the endoscopists who perform the exam are associated with CRC after a negative complete colonoscopy.

A cohort of Ontario residents, 50-80 years old, who had a negative complete colonoscopy between January 1, 1992, and December 31, 1997, was identified by using linked administrative databases. Cohort members had no history of CRC or inflammatory bowel disease or a recent colonic resection. Each individual was followed through December 31, 2006, and those with a new diagnosis of CRC were identified. Multivariable analysis was used to evaluate the association of patient, endoscopist, and procedure setting characteristics with incident CRC.

A cohort of 110,402 individuals with a negative complete colonoscopy was identified; the majority (86%) had their procedures performed in hospitals. During the 15-year follow-up period, 1596 (14.5%) developed CRC. There was no association between endoscopist colonoscopy volume and incident CRC. Among persons who had their colonoscopies at a hospital, those who had their procedures performed by a non-gastroenterologist were at significantly increased risk for developing subsequent CRC.

Endoscopist specialty is an important determinant of the effectiveness of colonoscopy in usual clinical practice. After a negative colonoscopy, those who have had their procedures performed by a gastroenterologist are less likely to develop CRC.