Guardant Health has put forward additional data to support its blood test to help catch early cases of colorectal cancer, showing its accuracy can be in the same range as other guideline-recommended screenings.
First launched in May 2022, the company’s Shield test searches for evidence of the disease by analyzing small fragments of tumor DNA found floating in the bloodstream.
At the annual Digestive Disease Week meeting, Guardant presented findings from its ECLIPSE study, which gathered findings from 20,000 patients. The Shield test posted an 83% overall sensitivity in correctly identifying people with colorectal cancer, or a 17% false-negative rate.
However, when splitting the results into cancer stages—from the earliest phases of growth to the most advanced—the test delivered 55% sensitivity at stage 1, or before a localized tumor has spread beyond the walls of the colon, and 100% sensitivity for stages 2, 3 and 4.
Shield also delivered 90% overall specificity, or a 10% rate of false positives. Guardant said that its combined findings approach the range of other noninvasive screening methods for colorectal cancer, such as fecal immunochemical tests (FITs), also known as stool tests.
FIT screening sensitivity in non-metastatic disease can reach 73%, the company said, while the Shield test’s combined sensitivity for stages 1, 2 and 3 comes to 81%. But Guardant claims its blood test may be easier for some people to stomach with a simpler trip to the doctor’s office.
The company has also described its test as a complement to colonoscopy; people who receive a positive result as a first step should then be referred for the procedure for confirmation. Guardant has estimated that a third of adults have not completed the recommended set of screenings, with colonoscopies every 10 years and annual stool-based tests starting at age 45.
“There is an unmet need in CRC screening for a high-performance screening test that gets completed,” Guardant co-CEO AmirAli Talasaz, Ph.D., said in a statement. “We believe that as a longitudinal screening test, taken every three years, Shield would detect nearly all CRCs at a curable stage and will save many lives.”
According to the company, colorectal cancer is the third leading cause of cancer-related death, but 49 million people in the U.S. remain unscreened, with those rates being lower among minority and underserved populations.