A Closer Look At The New Blood Test For Colon Cancer
Cancer General Health & Wellness Aging Well
November 18, 2024
The U.S. Food and Drug Administration (FDA) recently approved a blood test that can spot colon cancer. Sound too good to be true? In some ways, it is.
The FDA approved the blood test in July 2024 as a primary screening option for colon cancer. This means providers can offer a blood test similarly to other noninvasive screening methods, which include stool-based tests. However, all noninvasive tests are less accurate than colonoscopy.
Key Takeaways: Blood Testing For Colon Cancer
- While convenient, colon cancer blood work doesn't detect all cases of colorectal cancers, and the blood tests detect only 13% of dangerous polyps.
- A positive test result on your blood test may require a follow-up colonoscopy.
- A screening colonoscopy is the recommended tool for screening people who are at average risk for colon cancer.
Will A Blood Test Detect Colon Cancer?
Colonoscopy is the gold standard for screening people who are at average risk for colon cancer. As effective as colonoscopy is for stopping colorectal cancer, many adults put this routine cancer screening off indefinitely.
"The blood test is by no means perfect, but it is certainly a better option than not getting screened at all," said Niraj Gupta, MD, a medical oncologist with Franciscan Physician Network in Carmel, Indiana. "The same can be said for stool-based tests. These tests detect hidden blood or abnormal genetic material in the stool, which are possible signs of colon cancer. But they aren’t as accurate as a colonoscopy either."
Dr. Gupta added that if a blood test or stool-based test is positive, you will need a follow-up colonoscopy to help your care team learn more.
How Accurate Is The Colon Cancer Blood Test?
The main issue with blood tests and stool tests for colorectal cancer is that, unlike colonoscopies, they often miss precancerous growths on the colon. These growths, also called polyps, can be removed during a colonoscopy, potentially preventing colon cancer.
The blood tests detect 83% of colorectal cancers but only 13% of dangerous polyps. In contrast, colonoscopies find 95% of dangerous polyps, and the most advanced fecal test finds 42%. The American Gastroenterological Association also warns about the risk of false positives or false negatives in colon cancer blood work.
Another disadvantage of these blood tests is cost. Although FDA-approved, the blood test costs hundreds of dollars. Medicare covers the cost. Other insurance plans may not cover the cost of this test yet, but may start covering it soon. Check with your insurance plan about coverage of blood tests for colorectal cancer screening.
The Importance Of Colorectal Cancer Screening
Colorectal cancer is the third-most common cancer in adults in the United States. It is the second-leading cause of cancer death.
"If everyone followed the American Cancer Society’s colon cancer screening recommendations, far fewer people in this country would get the disease or die from it," Dr. Gupta said.
The American Cancer Society recommends colorectal cancer screenings beginning at age 45 unless you have a family history of colorectal cancer or other risk factors for the disease.
If you are at higher risk for colorectal cancer, colonoscopy is the only recommended screening option. Talk to your primary care provider about starting screenings earlier. You may also want to discuss getting them more frequently than people at average risk.
Talk To Your Doctor About What’s Best For You
The new colon cancer blood test may be a good alternative for people who refuse to schedule a colonoscopy. But the test isn’t as accurate as a colonoscopy, nor can it be used to remove precancerous polyps.
Your health is important. Talk to your primary care provider to see if you are due for a colon cancer screening. Ask what type is best for you.
