Guardant Health’s Shield blood test for colorectal cancer (CRC) screening was recently approved by the U.S. Food and Drug Administration (FDA). It’s indicated for people aged 45 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 CRC. Shield is also the first blood test for CRC screening that meets the requirements for Medicare coverage.
While Shield is a pioneer, it’s by no means alone in the field. There are over 1000 liquid biopsies for cancer in development.
The FDA decision follows results from the study, published in the March 14, 2024, issue of The New England Journal of Medicine , that showed that Shield demonstrated 83% sensitivity for the detection of CRC, with 90% specificity for advanced neoplasia.
Colorectal cancer is the second-leading cause of cancer-related death in the U.S., but it is highly treatable if caught early. The American Cancer Society estimates that more than 150,000 people will be diagnosed with CRC in 2024 and the disease will be responsible for more than 53,000 deaths. More than three out of four individuals who die from CRC are not up to date with their screening.
The rate of colon cancer has also increased substantially among younger people. It’s an alarming trend that led the U.S. Preventative Services Task Force to change its recommendations in 2021 for colon cancer screenings to begin at age 45.
A key challenge is to get more people screened. The CRC screening rate in the U.S. is only about 59%—more than one out of three eligible Americans—over 50 million people—do not complete CRC screening likely because the other options, such as colonoscopy or stool-based tests, are regarded as 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, gastroenterologist at Massachusetts General Hospital and professor of medicine at Harvard Medical School.
He added that, “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 CRC screening into a new era. With increased screening rates and early cancer detection, many more lives can be saved.”
The Shield test can be considered in a manner similar to guideline-recommended non-invasive CRC screening options and can be completed during any healthcare visit. A positive Shield result raises concern for the presence of colorectal cancer or advanced adenoma and the patient should be referred for colonoscopy evaluation.
“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.”
