Colorectal cancer risk factors in the detection of advanced adenoma and colorectal cancer.

Several risk factors for colorectal cancer (CRC) have been identified. If individuals with risk factors are more likely to harbor cancer or it precursors screening programs should be targeted toward this population. We evaluated the predictive value of colorectal cancer risk factors for the detection of advanced colorectal adenoma in a population based CRC colonoscopy screening program. Data were collected in a multicenter trial conducted in the Netherlands, in which 6600 asymptomatic men and women between 50 and 75 years were randomly selected from a population registry. They were invited to undergo a screening colonoscopy. Based on a review of the literature CRC risk factors were selected. Information on risk factors was obtained from screening attendees through a questionnaire. For each CRC risk factor, we estimated its odds ratio (OR) relative to the presence of advanced neoplasia as detected at colonoscopy. Of the 1426 screening participants who underwent a colonoscopy, 1236 (86%) completed the risk questionnaire. 110 participants (8.9%) had advanced neoplasia. The following risk factors were significantly associated with advanced neoplasia detected by colonoscopy: age (OR: 1.06 per year; 95% CI: 1.03-1.10), calcium intake (OR: 0.99 per mg; 95% CI: 0.99-1.00), positive CRC family history (OR: 1.55 per first degree family member; 95%CI: 1.11-2.16) and smoking (OR: 1.75; 95%CI: 1.09-2.82). Elderly screening participants, participants with lower calcium intake, a CRC family history, and smokers are at increased risk of harboring detectable advanced colorectal neoplasia at screening colonoscopy.