Risk Stratification Could Improve Precision in Colon Cancer Screening

A novel risk-stratification index can help avoid unnecessary colonoscopies in individuals at low-risk for developing colorectal cancer.

Researchers have developed a risk-stratification index that will stratify patients who have an average risk of developing colorectal cancer (CRC). This system would enable tailoring of screening within this group, with less invasive tests (sigmoidoscopy or occult blood tests) for lower-risk persons and colonoscopy for higher-risk persons. The researchers believe this could improve the uptake of CRC screening, which is currently underutilized but recommended for those over 50 years of age.

This cross-sectional study, published in the Annals of Internal Medicine, included persons between 50 and 80 years of age who were undergoing initial colonoscopy in endoscopy units across the Midwestern regions of the country. The study period was December 2004 to September 2011.

Of the 4460 patients included in the study, 2993 were included in the derivation set and 1467 in the validation set. A clinical score was given based on the patient's complete health data and points from regression coefficients for age, sex, waist circumference, cigarette smoking, and family history. Of those in the derivation set, 9.4% had advanced neoplasia; risks for advanced neoplasia in individuals at very low, low, intermediate, and high risk were 1.92%, 4.88%, 9.93%, and 24.9%, respectively. Sigmoidoscopy to the descending colon in the low risk group would have detected 73% of advanced neoplams, the authors report. In the validation set, the corresponding risks for advanced neoplasias were 1.65%, 3.31%, 10,9%, and 22.3%, and sigmoidoscopy would have detected 87.5% of advanced neoplams.

The authors conclude that their risk stratification score identifies the lower-risk group among whom noncolonoscopy screening strategies can be effective and efficient. While avoiding patient discomfort, the risk-estimating index can also reduce healthcare costs associated with unnecessary screening colonoscopies, which also speaks to the aims of the Choosing Wisely initiative.