A novel blood test has shown significant potential in detecting colon cancer, achieving over 80% accuracy in identifying the disease and 90% accuracy in excluding it in healthy individuals. The findings, presented at the 2025 American Society of Clinical Oncology Gastrointestinal Cancers Symposium and published in the Journal of Clinical Oncology, suggest a less invasive method for colorectal cancer screening. This development could address the low screening rates currently observed, with a substantial portion of the eligible population not undergoing recommended tests.
Study Details
The study enrolled more than 27,000 adults between the ages of 45 and 85 from May 2020 to April 2022. Participants had blood samples taken before undergoing a colonoscopy, the standard screening procedure for colon cancer. Researchers analyzed the blood samples for "molecular signals of advanced colorectal cellular changes" and compared these results with the colonoscopy findings. The test's sensitivity, or its ability to correctly identify those with colon cancer, was 81.1%. Its specificity, the ability to correctly identify those without colon cancer, was 90.4%.
Expert Commentary
Dr. Aasma Shaukat, lead study author from NYU Grossman School of Medicine, emphasized the need for more accessible colorectal cancer screening options. "Additional colorectal cancer screening tests that are convenient, safe, and easy to complete are needed," she stated in a press release from ASCO. "Until now, we have only had stool-based tests and colonoscopy or sigmoidoscopy. A blood test has the potential for improving colorectal cancer screening rates."
Dr. Pamela Kunz from Yale School of Medicine, who was not involved in the study, described the blood test as a "new tool in our toolbox" for colorectal cancer screening. She added that the study indicates it "may provide a convenient and effective option for colorectal cancer screening in the average-risk U.S. population."
The Role of Liquid Biopsies
Dr. Pashtoon Kasi, medical director of gastrointestinal medical oncology at City of Hope Orange County in California, highlighted the transformative potential of blood tests, also known as "liquid biopsies," in cancer care. "It is a simple blood test looking at different components of cancers or tumors that are being shed in the bloodstream – hence, the term ‘liquid biopsy,’" Kasi explained. He noted that while some tests are cancer-specific, like this colon cancer test, others are multi-cancer early detection tests (MCED) capable of detecting multiple cancers from a single blood draw.
Blood Test vs. Colonoscopy
Despite the promise of blood tests, experts caution against using them as a replacement for colonoscopies. Dr. Kasi emphasized that colonoscopies remain the "gold standard" for colon cancer screening because they can prevent the disease through the detection and removal of precancerous polyps. "Blood tests are designed to detect cancer, not prevent it," he stated. If a blood test indicates the presence of cancer, a colonoscopy is still necessary for further evaluation.
Impact on Screening Rates
It is estimated that a significant proportion of the population does not undergo colon cancer screenings. The hope is that blood tests can help bridge this gap. Dr. Kasi noted that colonoscopies often evoke negative feelings due to the required bowel preparation and invasive nature of the procedure, making blood tests a more appealing option for many.
Future Directions
Researchers plan to continue studying the long-term effects of colorectal blood tests. Dr. Shaukat anticipates that these tests will become more widely available as they gain approval from regulatory bodies and insurance providers. Blood-based tests are currently considered an option for men and women between 45 and 85 who are at average risk for colon cancer and due for screening. However, they are not suitable for individuals with a high-risk family history or other medical conditions that increase their risk of colon cancer.
