Cell-Free DNA Test Has High Sensitivity for Colorectal Cancer

A blood-based cell-free DNA (cfDNA) test was able to find patients at increased risk of colorectal cancer (CRC), advanced neoplasia, and advanced precancerous lesions among those who were at average risk, according to a study published in The New England Journal of Medicine.

CRC is the second leading cause of cancer-related death in the US, with 53,000 patients expected to die from CRC in 2024 alone. The US Preventive Services Task Force has recommended that screening for CRC, even when persons are not symptomatic, is the primary mode of prevention for deaths and incidence. However, low screening still persists, with barriers including the time it takes for a screening test, concern and fear of the pain of the test, lack of availability, and lack of insurance coverage. The blood-based test could provide an alternative for patients to allow for screening during visits to the doctor. This study aimed to assess the efficacy of this test in identifying those at higher risk of CRC among those of average risk.

Colorectal cancer | Image credit: mi_viri - stock.adobe.com

This study enrolled participants from 265 primary care and endoscopy sites across the US. All participants were aged 45 to 84 years and needed their routine screening for CRC. They were also at average risk of CRC. Participants who had a history of cancer, hereditary disposition to CRC, a family history of CRC, inflammatory bowel disease, and a recent CRC screening were excluded.

Participants had their blood drawn prior to their screening for CRC, which needed to occur within 60 days of enrollment, with some exceptions due to the pandemic. Repeated colonoscopies were allowed within the time frame. The primary outcomes were sensitivity to CRC and advanced neoplasia, and sensitivity for precancerous lesions was the secondary outcome.

There were 7861 participants who were enrolled between October 2019 and September 2022 who had a mean age of 60 years and of whom 53.7% were women. The cohort was primarily White (78.5%) with Asian (7.1%) and Black (11.8%) participants represented in smaller numbers; 13.3% of participants identified as Hispanic or Latino.

There were 65 participants who had CRC detected by a colonoscopy, of which 83.1% had a positive cfDNA test. This indicated a sensitivity of 83.1% (95% CI, 72.2%-90.3%). Screening-relevant CRC was detected in 42 of 48 blood tests, which is a sensitivity of 87.5% (95% CI, 75.3%-94.1%); 11 of 17 stage I cancers were also detected with the blood test, for a sensitivity of 65% (95% CI, 41%-83%). Stage IV cancer was detected in 10 of 10 CRC cases, or 100% sensitivity (95% CI, 72%-100%). Primary tumor location, tumor histologic grade, and demographic characteristics did not affect sensitivity.

The cfDNA test correctly assessed negative advanced colorectal neoplasia results in 89.6% of cases (95% CI, 88.8%-90.3%). For the secondary outcome, the sensitivity for finding advanced precancerous lesions was 13.2% (95% CI, 11.3%-15.3%) when using the cfDNA test.

The researchers concluded that the cfDNA blood-based test could assess participants of average risk for CRC with an 83% sensitivity for CRC and a 90% specificity for advanced neoplasia, both of which are high values for regular use.

Reference

Chung DC, Gray II DM, Singh H, et al. A cell-free DNA blood-based test for colorectal cancer screening. N Engl J Med. 2024;390(11):973-983. doi:10.1056/NEJMoa2304714