2024/05/27 Revolutionary Blood Test Promises Easier and More Accurate Colorectal Cancer Screening

Revolutionary Blood Test Promises Easier and More Accurate Colorectal Cancer Screening
A groundbreaking study has revealed the potential of a blood-based test to significantly enhance colorectal cancer (CRC) screening. Despite being the third most diagnosed cancer in adults in the United States, more than one-third of the screening-eligible population is not up to date with their CRC screenings. Early detection could prevent over 90% of CRC-related deaths, but current screening methods, such as colonoscopies and stool tests, are often perceived as invasive or inconvenient, leading to low adherence rates.
Guardant Health, a biotechnology company based in Palo Alto, California, has developed a promising alternative: the Shield blood test. This test is designed to detect early signs of CRC using cell-free DNA (cfDNA) in blood samples. Recently, the FDA's Molecular and Clinical Genetics Panel of the Medical Devices Advisory Committee evaluated the Shield test, examining its safety, effectiveness, and overall benefit-risk profile.
The study, which included nearly 8,000 participants, showed that the Shield test had an 83.1% sensitivity for detecting CRC and a 90% specificity for advanced neoplasia (CRC or advanced precancerous lesions). Sensitivity for detecting early-stage CRC (stages I, II, or III) was even higher at 87.5%. Also, the test’s high specificity suggests it could effectively identify individuals without advanced neoplasia, reducing unnecessary follow-up procedures.
The FDA panel voted 8-1 that the Shield test is safe, 6-3 that it is effective, and 7-2 that its benefits outweigh the risks. These votes will be considered by the FDA, which will decide whether to approve the test. If approved, Shield would become the first FDA-approved blood-based CRC screening test eligible for Medicare reimbursement, potentially increasing screening adherence by offering a more convenient, non-invasive option.
Current CRC screening options, including annual or triennial stool-based tests, decennial colonoscopies, and quinquennial virtual colonoscopies or sigmoidoscopies, have varied acceptance among patients. The introduction of the Shield test could provide a valuable alternative, particularly for those reluctant to undergo existing methods. While not a replacement for traditional screenings, the Shield test represents a significant advancement in CRC detection, offering a promising tool in the fight against one of the most deadly yet preventable cancers.