U.S. health regulators have approved the first blood test for colon cancer, a significant step in cancer screening. The test, called Shield, is manufactured by Guardant and has been approved by the Food and Drug Administration (FDA) for adults aged 45 and older with an average risk of colon cancer.
The Shield test offers a noninvasive alternative to colonoscopies, though it is not intended to replace them. It detects DNA fragments shed by tumor cells and precancerous growths. In a study published in March, the test identified 83% of cancers but detected very few precancerous growths compared to colonoscopy, which remains the gold standard for colon cancer screening. The Shield test missed 17% of cancers, performing similarly to stool-based tests.
Doctors can currently order the Shield test for patients at an out-of-pocket cost of $895. FDA approval is expected to lead to broader coverage by private and government insurance plans.
Colonoscopies are crucial as they not only detect tumors but also prevent the disease by removing precancerous polyps. However, many people avoid colonoscopies due to the inconvenience of taking time off work and the preparation required the day before the procedure, which involves drinking a strong laxative to empty the bowels.
In the U.S., it is recommended that healthy adults aged 45 to 75 with an average risk of colon cancer undergo regular screening.
