Can a Blood Test Screen for Colon Cancer? Guardant Health Chief Medical Officer Shares Promising Update

In the fight against colon cancer, early detection is critically important. However, not everyone who should be getting screened, typically with a colonoscopy, is doing so.

“Colon cancer is the second leading cause of cancer death and it most commonly affects people who aren’t up to date with their screening,” Dr. Craig Eagle, the Chief Medical Officer at Guardant Health, told SurvivorNet. “If we can get people up to date with screening, we can actually reduce the death rate of colon cancer.

“An ounce of prevention is worth a pound of cure,” he added.

That’s why Guardant is currently testing its “Shield” product, which aims to increase screening rates by offering a simpler, less time-consuming, and less invasive screening option.

Can a blood test really detect colon cancer?

“The cancer diagnostic test has been available as what we describe as a laboratory-developed test, or LDT, and this is the first stage in getting the test to move forward,” Dr. Eagle explained.

The next step for Guardant is to bring research showing the test’s effectiveness to the Food and Drug Administration (FDA) for approval. There are many challenges when creating blood tests to screen for cancer, one of which is ensuring there isn’t a rise in false positives.

According to current guidelines in the U.S., average-risk adults between the ages of 45 and 75 should undergo regular colon cancer screening, whether that is through a colonoscopy (in which a thin tube is inserted to look for signs of cancer in the rectum and colon) or a stool test.

Adding the blood test as a potential option will ideally help reduce the number of people skipping recommended screenings, Dr. Eagle said.

“This is another option for people to have screening who may not prefer to deal with methods that involve the stool or the actual bowel,” he explained.

“One of the things we realized is there’s a target to try and screen up to 80% of people in the U.S. to prevent colon cancer and we’re not there yet … This is where we believe Shield can add value as well, for those people who should be screened but are not going through with the current testing methodology.”

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