FDA Approves First Blood Test For Colon Cancer Detection

The FDA has approved a new blood test that can be used to detect colon cancer. Doctors say this blood test can reduce the number of colonoscopies and increase screening rates.

The Shield test, the first of its kind for colon cancer, uses DNA in the blood to screen for the disease.

"Some of these fragments of DNA that are unique to colon cancer released in the blood can now be detected by a blood test,” said Dr. Harvey Tatum, a gastroenterologist at the Utica Park Clinic.

Tatum says the test can be administered during a routine health screening.

"We will do many unnecessary colonoscopies on people that don't have any risk or very small polyps that have low risk of progressing,” said Tatum. “If we can find the patients that have high-risk polyps or colon cancer markers, we can perform fewer colonoscopies but have more value because we do them on people who really need them."

Studies show the test is about 83% accurate, meaning if you have colon cancer or an advanced polyp, there is an 83% chance the test will be positive and a 17% chance it will be negative.

"Any test we do for a screening has the chance to be falsely positive or falsely negative,” said Tatum. “The value of this test is it seems to have a high level of accuracy for detecting cancer, as opposed to just finding blood in the stool."

Tatum says the only way to prevent colon cancer is still to remove polyps during a colonoscopy before they become cancerous. However, this test is a valuable tool in deciding whether to get a colonoscopy. "Colon cancer is preventable,” said Tatum. “As part of your routine health screening, in addition to things like cholesterol and blood pressure, this should be part of the routine screening starting at age 45.”

Doctors recommend everyone aged 45 and older get screened for colon cancer. Tatum notes it’s still unclear when this test will be available to the public as it awaits insurance approval, but it’s a good conversation to have with your doctor.