A new study looking at a non-invasive blood assay method to detect early colorectal cancer (CRC) could eventually mean the end of regular colonoscopy for CRC screening. The test capitalizes on new, more sensitive methods to detect circulating cells in the blood and looks at three blood markers: circulating gastrointestinal epithelial cells, somatic mutations and methylation of cell-free DNA.

Researchers tested the assay in 354 patients who were already scheduled for their regular screening colonoscopy with no previous CRC diagnosis – 14% of patients had experienced symptoms or a positive fecal immunochemical test and 86% were asymptomatic. When compared to findings during colonoscopy, the blood test proved a sensitivity (true positives) of 100% for detecting CRC and 76% for detecting advanced adenomas (pre-cancerous polyps).

Takeaway: Colonoscopy has the ability to look for pre-cancerous polyps as well as remove them, but it’s invasive nature and the requirement for sedation make it less appealing than other non-invasive tests, which have historically been less accurate. This new blood test is both highly sensitive and very convenient for patients. Researchers plan to test the blood assay in a larger multi-center trial as the next step in the goal of making the test available to all in the future.

In the meantime, if you are 45 years or older and are due for your screening colonoscopy, it’s recommended that you go ahead and schedule the procedure once you are able to do so, especially if you are in the high-risk category.  

Friedland S, et al. Abstract 575. Presented at: Digestive Disease Week; May 2-5, 2020; Chicago (meeting canceled).