New colorectal cancer blood test approved by FDA: What to know

• The Food and Drug Administration (FDA) has recently approved a blood test that can assist in the primary detection of colorectal cancer.
• This test could assist with prompt detection and intervention for this prevalent cancer type. Doctors and specialists can offer appropriate guidance for people who would most benefit from it.
• Currently, the test is not covered by Medicare, but this could change in the future, as well as potential coverage from private health insurance groups.

Colorectal cancer is the third most common type of cancer in the world. It can sometimes be challenging to treat, making early detection and diagnosis critical.

However, screening options like colonoscopies can be uncomfortable and difficult for people to do. Research is ongoing about different tests that can help detect colorectal cancer to ensure the best possible health outcomes.

Recent steps suggest that options for colorectal cancer screening are continuing to expand.

Why did the FDA approve the new colon cancer blood test?

On July 29, 2024, the Food and Drug Administration (FDA) approved a blood test that can help with primary colorectal cancer screening.

The test is Guardant Health’s Shield blood test, and the approval is a critical step towards making it available to the general population.

The approval came after a study published in the New England Journal of Medicine in March 2024. The study noted that over a third of people who are eligible for colorectal cancer screening are not up to date with screening.

It looked at data from almost 8,000 participants, and found that this blood test was just over 83% successful at detecting colorectal cancer.

William M. Grady, MD , professor of translational science and therapeutics division at the Fred Hutch Cancer Center, and one of the authors of this study, explained a little more about the test to Medical News Today :

“The Shield blood test is a screening test for colorectal cancer that is as accurate as the most commonly used stool-based test, FIT, for detecting colorectal cancer. It has a false negative rate of 13% and a false positive rate of roughly 10%. It detects 13% of advanced colon adenomas, which are the precursors to colorectal cancer.”

“The Shield test is an option for colorectal cancer screening and is more convenient than doing the other recommended screening tests, FIT, Cologuard, and colonoscopy. However, it is not as accurate as colonoscopy or Cologuard for detecting advanced colon adenomas or CRC and is not as accurate as FIT for detecting advanced colon adenomas,” he added.

Who is this blood test for?

Specific screening recommendations for colorectal cancer can vary. However, the U.S. Preventive Services Task Force recommends that most adults begin colorectal cancer screening at age 45.

Different testing options include different analyses of stool samples, flexible sigmoidoscopies, and colonoscopies. People can work with their doctors and other specialists to determine their risk for colorectal cancer and their screening needs.

This newly approved primary screening blood test is for adults who are 45 years old or older, and have an average risk for colorectal cancer.

Grady explained that “the Shield test is an appropriate screening test for those people who understand the lower accuracy of the test compared to the other available screening tests and who are at average risk of colorectal cancer.”

How does this blood test work?

People who get this test just need to get a blood draw, which is typically straightforward and similar to other lab work that is already a part of clinical practice.

As the previously referenced study noted, the test is a cell-free DNA blood-based test. This type of analysis looks at non-cellular DNA in the blood sample.

People interested in this test can speak with their doctors to see if this testing option is a good choice for them.

Uri Ladabaum, MD, MS , professor of medicine, and director of the GI Cancer Prevention Program at Stanford University School of Medicine, who was not involved in this study, offered some words of caution about colorectal cancer screening options, and where this test fits on the spectrum of options:

“Colonoscopy and stool tests are better than Guardant Shield at detecting pre-cancerous polyps, and they are expected to be better than Guardant Shield at preventing people from getting or dying from colorectal cancer. Patients and doctors should weigh the expected benefits of the various options vs. the ease of use
when making individualized, informed decisions. Patients must understand that a ‘positive’ (abnormal) stool test or Shield test must be followed by a colonoscopy in order to maximize the chances of finding cancer at a curable stage, or of removing polyps before they become cancer.”

Blood test provides less invasive screening alternative

This test gives clinicians one more option to present to people who are seeking out options to screen for colorectal cancer. This could help improve survival rates among people with colorectal cancer, as colorectal cancer is the second leading cause of cancer-related death.

This recently approved blood test could help close current gaps in colorectal cancer screening, particularly because of high patient adherence levels.

Since the test causes minimal discomfort, people might be more willing to get this test and thus be more on top of colorectal cancer screening.

Anton Bilchik, MD, PhD , a surgical oncologist, chief of medicine, and director of the Gastrointestinal and Hepatobiliary Program at Providence Saint John’s Cancer Institute in Santa Monica, CA, who was not involved in the research on this test, noted that:

“Colorectal cancer is one of the most rapidly growing cancers in young people today. In fact, it is the leading cause of cancer related deaths in males younger than 40. Many people, especially younger patients are reluctant to do screening colonoscopies or home-based stool tests. This offers a simple alternative to detecting colon cancer at a curable stage.”

Does Medicare cover this test?

Insurance coverage of screening tests in the U.S. is often complicated, as there are multiple private insurance groups and the federally funded options of Medicare and Medicaid .

It may take time for the test to gain popularity and show beneficial results in direct clinical practice.

While coverage may be further down the road, the blood test does meet Medicare coverage requirements .

Bilchik noted the following action steps that may need to happen before the test starts to be covered by Medicare:

“This blood test does not detect pre-cancerous polyps […] More studies are needed to compare this test to commercially available stool-based tests. Also the current cost is about $895 per test which is significantly more expensive than the stool based tests. Further value-based analyses will be needed prior to widespread coverage by private insurance companies and Medicare.”