Predictors of Interval Cancers After Negative Colonoscopy

About 5% of colorectal cancers (CRCs) develop within 3 years of negative colonoscopy. These “interval” CRCs are more likely to occur in the proximal colon than in the distal colon and to demonstrate microsatellite instability and the CPG island methylator phenotype (JW Gastroenterol Jan 29 2010).

In a retrospective, population-based study designed to identify clinical factors associated with interval CRCs (defined as occurring 3–36 months after negative colonoscopy), investigators in Manitoba, Canada, assessed more than 45,000 healthy individuals (age, ≥40) who had negative colonoscopies performed between 1989 and 2006. Although the prevalence of symptoms in the study population was unknown, many of the patients were likely symptomatic, give…