An accurate, noninvasive test could improve the effectiveness of colorectal-cancer screening.
Dr Thomas Imperiale and colleagues compared a noninvasive, multitarget stool DNA test with a fecal immunochemical test (FIT) in persons at average risk for colorectal cancer.
The DNA test includes quantitative molecular assays for KRAS mutations, aberrant NDRG4 and BMP3 methylation, and β-actin, plus a hemoglobin immunoassay.
Results were generated with the use of a logistic-regression algorithm, with values of 183 or more considered to be positive.
|The sensitivity for detecting colorectal cancer was 92% with DNA testing|
|New England Journal of Medicine|
FIT values of more than 100 ng of hemoglobin per milliliter of buffer were considered to be positive.
Tests were processed independently of colonoscopic findings.
Of the 9989 participants who could be evaluated, the team found that less than 1% had colorectal cancer, and 8% had advanced precancerous lesions on colonoscopy.
The sensitivity for detecting colorectal cancer was 92% with DNA testing, and 74% with FIT.
The research team found that the sensitivity for detecting advanced precancerous lesions was 42% with DNA testing, and 24% with FIT.
The team noted that the rate of detection of polyps with high-grade dysplasia was 69% with DNA testing, and 46% with FIT.
The researchers observed that the rates of detection of serrated sessile polyps measuring 1 cm or more were 42% and 5%, respectively.
Specificities with DNA testing and FIT were 87% and 95%, respectively, among participants with nonadvanced or negative findings, and 90% and 96%, respectively, among those with negative results on colonoscopy.
The team found that the numbers of persons who would need to be screened to detect one cancer were 154 with colonoscopy, 166 with DNA testing, and 208 with FIT.
Dr Imperiale's team concludes, "In asymptomatic persons at average risk for colorectal cancer, multitarget stool DNA testing detected significantly more cancers than did FIT but had more false positive results."