A Risk Score to Predict Colorectal Cancer

Age and family history inform recommendations for colorectal cancer (CRC) screening, but other risk factors have been identified. In this study, researchers used two long-term U.S. cohort studies — the Nurses' Health Study and the Health Professionals Follow-Up Study — to examine 8 risk factors known to be associated with excess incidence of CRC: Family history, smoking, higher body-mass index, less physical activity, unhealthy diet, alcohol use, tall stature, and lack of aspirin use (specific definitions for each risk factor are detailed in an online supplement published with the original article). About 120,000 participants (mean age, 54) were followed for a median 26 years.

Adjusted analyses revealed the following:

• 10-year risk for CRC in low-risk participants (0–2 risk factors) was 0.85% in those who had not undergone screening colonoscopy and 0.70% among those who had undergone colonoscopy. In contrast, in high-risk people (6–8 risk factors), these percentages were 1.99% and 1.65%, respectively.
• 10-year CRC-related mortality in low-risk participants (0–2 risk factors) was 0.15% without screening colonoscopy and 0.08% with it. In contrast, in high-risk people (6–8 risk factors), these percentages were 0.44% and 0.22%, respectively.