The FDA on July 29 approved a screening test for colorectal cancer that requires only a blood sample.
Here are five things to know:
What is it?
Created by Guardant Health, the blood test, known as Shield, was able to detect 83% of colorectal cancers in studies but only 13% of dangerous polyps. Colonoscopies find approximately 95% of these polyps.
Shield is approved for patients 45 and older who are at average risk for colon cancer. Experts say the hope is that, despite detection limitations, the less invasive blood test will encourage more Americans to get screened. The test also showed a 10% false positive rate in studies.
How do gastroenterologists view it?
Many GI leaders are excited about the new test, citing its convenience and potential to increase screening accessibility.
"I am very excited about the new Shield circulating tumor blood test, which screens for colon cancer-related DNA markers in the blood," Benjamin Levy III, MD, gastroenterologist at University of Chicago Medicine, told Becker's. "There are many patients who would prefer blood-based screening instead of a colonoscopy or stool-based testing. The convenience of screening for colorectal cancer with a simple blood draw is pretty amazing."
Healthcare leaders have stressed that although the new test offers a promising, less invasive method for detecting colorectal cancer, it is not intended to replace a colonoscopy. Instead, they highlight the test's potential to complement existing screening methods.
"The new FDA approval of the Shield test for colon cancer screening highlights the ongoing efforts to prevent or identify early colon cancers, which seem to be more prevalent in our younger population than ever before," Lauren Bleich, MD, a gastroenterologist with Miami-based Gastro Health, told Becker's. "While it highlights the need for colon cancer screening, as well as may allow us to reach a broader audience, especially with the long wait times for colonoscopy patients encounter, it should not be used in place of colonoscopy, which is the gold standard for colon cancer screening and prevention."
Why are some gastroenterologists skeptical?
Amol Akhade, MD, a medical oncologist, argued in an Aug. 27 commentary piece in Oncology News Central that the test is not accurate enough to surpass colonoscopies.
"Finding a blood-based test to screen for cancer is a dream for every oncology researcher. Imagine a simple blood test that can detect precancerous lesions or Stage 1 cancer in asymptomatic individuals," Dr. Akhade wrote.
"This would greatly benefit both oncologists and patients, potentially reducing cancer-specific mortality in the long term. The catch is that the test needs to be highly sensitive and specific to be clinically useful. Unfortunately, the recent approval of a blood-based colorectal cancer screening test by the FDA sets the bar too low, opening a dangerous Pandora's box."
While the noninvasive nature of these tests might mean that more people receive CRC screenings overall, Dr. Akhade questioned the tests' accuracy and ability to detect aggressive, precancerous lesions.
Why is it needed?
As many as 25% to 50% of people who should be undergoing routine colonoscopies are not, according to the FDA. Additionally, colorectal cancer rates among U.S. adults have hit record highs in recent years. The expected growth rate of CRC among U.S. men is 8%, and it is 7% for women.
But reimbursements for gastroenterologists have steadily declined in recent years. Between 2007 and 2022, unadjusted and adjusted average reimbursement for GI procedures dropped by 7% and 33%, respectively, according to a study published in The American Journal of Gastroenterology. Reimbursements for colonoscopy and biopsy decreased 38% during that period.
"I would love to see payers and clinicians sit down at a table and have a conversation about the benefit of early endoscopy for diagnosis and screening," Omar Khokhar, MD, a gastroenterologist at Illinois GastroHealth in Bloomington, told Becker's. "In particular, how EGD/colonoscopy can potentially prevent patient morbidity and decrease downstream cost to the healthcare system. Yes, endoscopy isn't cheap, but cancer is a bad diagnosis and is more expensive."
How could insurance affect new GI cancer screening options?
Although the FDA's approval of the test is a promising step in adoption of blood-based screening, some leaders are concerned that payer approvals could stand in the way.
William Sellers, MD, chief of robotic colorectal surgery at St. Charles Hospital in Port Jefferson, N.Y., and St. Catherine of Siena Hospital in Smithtown, N.Y., spoke with Becker's about the potential effect of payers on potential widespread adoption of the tool.
"Everything that comes out always comes down to what the insurance companies will cover," he said. "The one good thing I read about this is it does seem with FDA approval, Medicare will reimburse and cover this. Usually in most situations private insurance follows Medicare's example, though that's not always 100% the case. Every time we as physicians come up with new tech or treatment or a new plan that's going to benefit patients, it will not be effective if the insurance companies aren't going to reimburse, aren't going to pay for it."