FDA approves blood test for colon cancer detection
The Food and Drug Administration approved a blood test intended to detect colorectal cancer on Monday, expanding options for screening for the potentially deadly disease.
The blood test, called Shield, from company Guardant Health, Inc., is approved for screening adults age 45 and older who are at average risk for the disease. The approval follows promising results from a clinical study of the blood test from earlier this year.
The study, published in the New England Journal of Medicine in March, found the test correctly detected colorectal cancer in 83% of people confirmed to have the disease who were at average risk and not experiencing symptoms.
"The FDA approval of the Shield test is a significant victory for patients and an important milestone in Guardant Health's mission to conquer cancer with data," Guardant Health co-CEO AmirAli Talasaz said in a news release Monday. "Shield can help improve colorectal cancer screening rates so we can detect more cancers at an early stage, when they are treatable."
Shield is available by prescription for eligible individuals, and is expected to be covered for eligible Medicare beneficiaries, according to the news release.
The blood test's approval comes at a time when more Americans have been developing colon cancer, and at younger ages.
CBS News chief medical correspondent Dr. Jon LaPook, a gastroenterologist at NYU Langone Health, said at the time of the clinical study that a blood test is attractive option for screening because "it's relatively easy to do and there's no 'ick factor.'"
However, it will not replace colonoscopy, which remains the current gold standard for catching colon cancer early.
"The gold standard for colon cancer screening is colonoscopy because it can detect colon cancer in its earliest, most treatable stages and it can find and remove precancerous polyps before they have a chance to turn into cancer," LaPook said.
The Shield test detected many cancers at Stage 2 or later, LaPook said after the FDA issued approval. "It wasn't as good with Stage 1 cancers, the earliest ones ... and it's not very good at all for benign polyps."
He also noted that the blood test has a 10% false-positive rate, meaning 10% of positive results will turn out not to be cancer after further testing.
Colorectal cancer, once the fourth-leading cause of cancer deaths for people younger than 50, has leaped up the list, becoming the leading cause for men and ranking second for women, according to a study published earlier this year.
Colon cancer screening guidelines have shifted in recent years to try to catch cancer earlier, lowering the recommended age of first screening from 50 to 45 for adults with average risk.
Overall, colorectal cancer is the third most common cancer diagnosed in both men and women in the United States, according to the American Cancer Society. The organization anticipates 106,590 new cases of colon cancer in 2024.
"You absolutely save lives with colonoscopy," LaPook said. "Don't die of embarrassment. Use your words, talk to your health care provider, and get screened."