As screening methods for colorectal cancer (CRC) are limited by uptake and adherence, further options are sought.
A blood test might increase both, but none has yet been tested in a screening setting.
Dr Timothy Robert Church and colleagues from Minnesota, USA prospectively assessed the accuracy of circulating methylated SEPT9 DNA (mSEPT9) for detecting colorectal cancer in a screening population.
Asymptomatic individuals ≥50 years old scheduled for screening colonoscopy at 32 US and German clinics voluntarily gave blood plasma samples before colon preparation.
Using a commercially available assay, 3 independent blinded laboratories assayed plasma DNA of all colorectal cancer cases and a stratified random sample of other subjects in duplicate real time PCRs.
The researchers' primary outcomes measures were standardized for overall sensitivity and specificity estimates.
|Specificity was 92%|
The team enrolled 7941 men and women, with a mean age of 60 years.
Results from 53 colorectal cancer cases and from 1457 subjects without colorectal cancer yielded a standardized sensitivity of 48%.
The team found that colorectal cancer stages I–IV, values were 35%, 63%, 46% and 77%, respectively.
The research team found that specificity was 92%.
The team noted that sensitivity for advanced adenomas was low.
Dr Church's team concludes, "Our study using the blood based mSEPT9 test showed that colorectal cancer signal in blood can be detected in asymptomatic average risk individuals undergoing screening."
"However, the utility of the test for population screening for colorectal cancer will require improved sensitivity for detection of early cancers and advanced adenomas."