Dr Otto Lin and colleagues developed a risk index to identify low-risk patients who may be screened for colorectal cancer.
The researchers used computerized tomographic colonography instead of colonoscopy to assess risk.
The team retrospectively randomized 1512 asymptomatic persons aged 50 years or older who had undergone screening colonoscopy to derivation subgroups.
A further group of 1493 patients were randomized to validation subgroups.
The team developed a risk index based on age, sex, and family history from the derivation group.
|The stratified strategy detected 89% of advanced neoplasia|
The expected results of 3 screening strategies were compared.
The screening strategies included universal colonoscopy, and universal computerized tomographic colonography.
The researchers also evaluated a stratified strategy of colonoscopy for high-risk and computerized tomographic colonography for low-risk patients.
Outcomes for the 3 strategies were extrapolated from the known colonic findings in each patient.
The research team used sensitivity, and specificity values for computerized tomographic colonography from the medical literature to extrapolate outcomes.
The team then validated findings in the validation subgroup.
The reseachers found that in the derivation subgroup, universal colonoscopy detected 94% of advanced neoplasia.
In this group, universal computerized tomographic colonography detected only 70%.
The team noted that computerized tomographic colonography resulted in the largest number of procedures and patients undergoing both procedures.
The stratified strategy detected 92% of advanced neoplasia.
The team noted that this strategy required colonoscopy in 68%.
Use of the stratified strategy required computerized tomographic colonography in 36% of patients, with only 4% having to undergo both procedures.
In the validation subgroup, universal colonoscopy detected 94%.
The researchers observed that universal computerized tomographic colonography detected 71% of advanced neoplasia in this subgroup.
However, the stratified strategy detected 89%, requiring colonoscopy in 64% and computerized tomographic colonography in 40%.
Unlike universal computerized tomographic colonography, the stratified strategy was independent of sensitivity, specificity, and threshold for colonoscopy.
Dr Lin's team concludes, “The stratified strategy based on our risk index may optimize the yield of colonoscopic resources and reduce the number of patients undergoing colonoscopy.”