Patients who have had a negative colonoscopy are less likely to develop colorectal cancer over the next 10 years, but the magnitude of that reduced risk is lower among those with a family history of the disease, according to statistics from the Utah Population Database. Additional details include:

• The population studied consisted of more than 131,000 Utah residents at average risk of colorectal cancer.
• The standardized incidence ratio (SIR) of cancer was 0.15 at 1 year, 0.26 at 2-5 years, and 0.60 at 7-10 years following the colonoscopy, when compared to the general Utah population.
• But when patients with a first-degree relative were factored into a second analysis, a significantly lower incidence of cancer was observed only during the first 5 years of follow-up (SIR, 0.39).