Do Recent Epidemiologic Observations Impact Who and How We Should Screen for CRC?

Abstract

Colorectal cancer (CRC) screening is recommended to begin at age 50 for those patients with no significant family history of CRC. However, even within this group of average-risk patients, there is data to suggest that there may be variation in CRC risk. These observations suggest that perhaps CRC screening should be tailored to target those patients at higher risk for earlier or more invasive screening as compared to those individuals at lower risk. The strategy of how to identify those higher-risk patients may not be straightforward. One method might be to use single risk factors such as smoking or elevated BMI as has been suggested in the recent American College of Gastroenterology CRC screening guidelines. Another paradigm involves the use of models which incorporate several risk factors to stratify patients by risk. This article will highlight recent large studies that examine recognized CRC risk factors as well as review recently developed CRC risk models. There will also be a discussion of the application of these factors and models in an effort to make CRC screening more efficient.

Risk Scores for Predicting Advanced Colorectal Neoplasia in the Average-risk Population: A Systematic Review and Meta-analysis

“…Risk scores identified from this review might be used to tailor screening based on the risk of AN in that individuals might have an informed choice on the selection of screening modalities according to the score. For example, participants with a higher risk score might preferably be offered screening colonoscopy, during which adenomas can be directly identified and removed, whereas those with a medium or lower risk score might still be encouraged for screening tests that are less invasive than colonoscopy, such as stool tests [8, 62]. These risk‐adapted screening strategies might improve effectiveness and acceptance of currently employed screening modalities, as they reduce the burden of invasive procedures for those at lower risk while focusing on those with higher risk.…”

“…Most models included age, gender, FH and lifestyle or dietary factors for predicting CRC or AA. While age, sex and FH may be easily obtained, other lifestyle‐related factors such as smoking, alcohol consumption and dietary factors may be more difficult to ascertain [62]. For example, Kaminski et al [29] and Imperiale et al [30] measured smoking with pack‐years, while Murchie et al [43] and Kim et al [47] used smoking status (never smoking, previous smoking or current smoking) to assess smoking.…”

Adenoma Detection Rates for Screening Colonoscopies in Smokers and Obese Adults

“…Our main exposure variables, obesity and smoking, have been identified in several models as predicting the presence of advanced adenomas in large populations 37,38 . In addition, our findings were consistent when the results were stratified by two other powerful adenoma predictors, age and sex.…”

Smoking and Other Risk Factors in Individuals With Synchronous Conventional High-Risk Adenomas and Clinically Significant Serrated Polyps

“…There are several strengths in our analysis. Our main exposure variable, smoking, has been identified in several models as predicting the presence of advanced adenomas and SSA/P in previously published studies [43,44]. The large database of the NHCR, with nearly 20,000 screening colonoscopies included in this analysis, provided excellent power to examine the impact of smoking colonoscopy findings.…”