Personalized Colorectal Cancer Screening

Guidelines recommend that colorectal cancer (CRC) screening begin at age 50 in average-risk individuals and at earlier ages for all (or a subset, in some guidelines) of those with a family history of CRC or advanced adenomas. These recommendations are practical but suboptimal considering the wide range of actual risk within the enormous population they cover.

Toward the development of tailored risk assessment strategies, investigators developed CRC risk models using half of a patient database constructed from multiple study cohorts. The models incorporated family history, an “E” score based on 19 lifestyle and environmental factors (i.e., demographics, anthropometric measures, risk behaviors, diet, medical history, and medication use), and a “G” score based on 63 CRC-associated single nucleotide polymorphisms. The risk models were validated for predicting CRC risk in the other half of the patients in the database, and then used to calculate recommended ages to start screening (i.e., ages when risk reductions would be equal to those based on average-risk screening at 50 years).

Use of the E and G scores, particularly when combined, led to better risk stratification of when to start colonoscopy screening compared with use of family history alone. For example, men and women with a positive family history of CRC and a combined E–G score in the 90th percentile would start screening at ages 40 and 46, respectively, whereas men and women with an E–G score in the 10th percentile with a positive CRC family history would start at ages 51 and 59, respectively. Using the model, 15% of men and 62% of women with a positive family history would not begin screening until age 50.

In the “average-risk” group, men and women with an E–G score in the 90th percentile should start screening at 44 and 50, respectively, and in the 10th percentile, at 56 and 64 years.