Despite rising rates of colon cancer, two-thirds of Americans say they’d rather file their taxes than get a cancer-detecting colonoscopy, a national survey finds. AmirAli Talasaz and Helmy Eltoukhy aim to offer a more appealing screening option. Their company, Guardant Health, co-founded in 2012, developed the first-ever blood test for colon cancer, which was approved by the FDA in 2024.
The test, called Shield, works by looking for changes to DNA floating in the bloodstream, called cell-free DNA, which may signify the presence of a tumor or precancerous growths in the colon. In a study of over 20,000 patients published in The New England Journal of Medicine, Shield demonstrated 55% sensitivity for detecting stage I colorectal cancer, 13.2% for advanced precancerous lesions and 100% sensitivity for detecting stage II colorectal cancer—on par with other approved non-invasive methods, but less effective than a traditional colonoscopy. However, more than 90% of patients who were prescribed the test actually completed it—a significantly higher rate than what doctors typically see with traditional colonoscopy screenings.
“The gap in screening is partly due to the barriers related to traditional methods, including the inconvenience or unpleasantness,” says Talasaz. “We believe that by applying our expertise in genomic profiling to a blood test, we can offer a more convenient solution for colon cancer screening, one that would ultimately increase early detection and save lives.”
The test is now available and covered by Medicare throughout the U.S., with 6,400 tests administered since its FDA approval in July of 2024. Commercial insurance coverage is expected to expand pending future review and inclusion in guidelines by the American Cancer Society and the U.S. Preventive Services Task Force. Talasaz and his team are now evaluating the use of the Shield technology for screening in lung, breast, prostate and other cancers.