Interval colorectal cancer after colonoscopy

Abstract

Background: As more patients are screened for colorectal cancer a small but significant number of interval cancers develop after colonoscopy for colorectal cancer screening.

Materials and methods: We reviewed records of 75,314 adult patients who underwent colonoscopy for screening or diagnostic purposes between 1998 and 2006 inclusively, and identified 77 who developed interval cancers within the next 5 years. We reviewed their original endoscopic findings to determine the clinical and endoscopic factors that might predict a greater risk for future cancers.

Results: Patients aged ≥ 60 years had a higher risk of an interval neoplasm (P < .0001). Interval cancers were more common on the right side of the colon and in the hepatic flexure (both P < .0001). We did not observe an increased rate of interval cancers in patients with poor preparation (P = .799); however, examination completion rates did affect the rate of interval cancers (P = .016).

Conclusion: Better identification of higher risk patients and assurance of follow-up examinations might increase the percentage of colon cancers discovered at an early stage. Special attention to careful examination of the right colon is key.

Keywords: Cancer screening; Colonoscopy; Colorectal cancer; Interval cancer; Quality.