On July 29, the U.S. Food and Drug Administration (FDA) approved Guardant Health’s Shield blood test for colorectal cancer screening in adults aged 45 years and older who are at average risk for the disease. It is the first blood test to be approved by the FDA as a primary screening option for colorectal cancer, meaning health-care providers can offer Shield in a manner similar to all other noninvasive methods recommended in screening guidelines. Shield is also the first blood test for colorectal cancer screening that meets the requirements for Medicare coverage.
Gaps in Colorectal Cancer Screening
Colorectal cancer is the second-leading cause of cancer-related death in the United States, even though it is highly treatable if caught early. The American Cancer Society estimates that more than 150,000 people will be diagnosed with colorectal cancer in 2024 and that the disease will be responsible for more than 53,000 deaths.
More than three out of four individuals who die from colorectal cancer are not up to date with their screening. Early detection of the disease is critical—when colorectal cancer cancer is found at an early stage before it has spread, the 5-year relative survival rate is 91%; if the cancer has metastasized, the 5-year relative survival rate is 14%.
The colorectal cancer screening rate in the United States is only about 59%, which falls well below the National Colorectal Cancer Roundtable’s goal of 80% for eligible individuals. More than one out of three eligible Americans—over 50 million people—do not complete colorectal cancer screening, often due to the perception that other available options—such as colonoscopy or stool-based tests—are invasive, unpleasant, or inconvenient.
“The persistent gap in colorectal cancer screening rates shows that the existing screening options do not appeal to millions of people,” said Daniel Chung, MD, a gastroenterologist at Massachusetts General Hospital and Professor of Medicine at Harvard Medical School. “The FDA's approval of the Shield blood test marks a tremendous leap forward, offering a compelling new solution to close this gap. This decision will help make screening tests more broadly accessible and propel blood-based testing and colorectal cancer screening into a new era. With increased screening rates and early cancer detection, many more lives can be saved.”
More About Shield
The Shield blood test is the result of over 10 years of research and development, including collaboration between Guardant Health and leading health organizations globally. Since the commercial introduction of the laboratory-developed test version in May 2022, the overall adherence rate for the Shield test has been more than 90%, meaning more than 90% of patients who were prescribed the test in a real-world clinical setting completed it. Primary care physicians can have patients complete a Shield test with a simple blood draw during a routine office visit, providing a more convenient and pleasant alternative screening method that doesn’t require the special preparation, dietary changes, time, and discomfort associated with colonoscopy, or the unpleasantness of handling stool.
The FDA decision follows a strong recommendation for approval by an Advisory Committee panel in May 2024. The approval was based on results of ECLIPSE, a registrational study involving more than 20,000 patients evaluating the performance of the test for detecting colorectal cancer in average-risk adults. Designed to reflect the diverse population of the United States, the study was conducted at more than 200 clinical trial sites in rural and urban communities across 37 states. Results from the study, published by Chung et al in March 2024 in The New England Journal of Medicine, showed that Shield demonstrated 83% sensitivity for the detection of colorectal cancer, with 90% specificity for advanced neoplasia. This performance is within range of current guideline-recommended noninvasive screening methods, in which overall colorectal cancer sensitivity ranges from 74% to 92%.
“This is a promising step toward making more convenient tools available to detect colorectal cancer early while it is more easily treated,” said William M. Grady, MD, a gastroenterologist at Fred Hutchinson Cancer Center. “The test, which has an accuracy rate for colon cancer detection similar to stool tests used for early detection of cancer, could offer an alternative for patients who may otherwise decline current screening options."
