The U.S. Food and Drug Administration (FDA) has approved a new blood test called Shield, made by Guardant Health, to screen for colon cancer in certain individuals. Although this test has been available commercially, FDA approval will help increase its availability and insurance coverage.
What is the Shield Test?
The test is approved for people aged 45 and older with an average risk of colon cancer. While Shield offers a less invasive and quicker screening option, it is not as accurate as a colonoscopy. Colonoscopies can detect and remove precancerous polyps and are recommended every 10 years, whereas the blood test needs to be done every three years.
In clinical trials, Shield had an 83.1% sensitivity rate (correctly identifying patients with cancer) and an 89.9% specificity rate (correctly identifying patients without cancer). However, it had a 10% false positive rate and detected only 13% of large polyps compared to 95% with a colonoscopy. The test works by detecting DNA shed by tumors in blood samples, with results available about two weeks after the samples are received by the laboratory.
Colon Cancer in the United States
Colon cancer is a major health issue in the U.S., with thousands diagnosed each year. It is one of the leading causes of cancer-related deaths. The disease has been affecting younger people more frequently in recent years. Early detection of colon cancer is crucial because it increases the chances of successful treatment. Screening helps find cancer at an early stage when it is more treatable. It can also detect precancerous polyps that can be removed before they turn into cancer.
What the Future Holds
The approval of the Shield blood test is seen as a significant step forward in cancer screening. This is not a replacement for colonoscopies. However, it provides an additional option for those who might avoid or delay traditional screenings due to the invasive nature of colonoscopies. The convenience of a blood test might encourage more people to get screened. This could potentially lead to earlier detection of colon cancer. Physicians can now tailor screening options to the individual needs of their patients. The hope is this will improve compliance with screening recommendations.
The FDA’s approval of the Shield test marks an important milestone in the fight against colorectal cancer. By offering a less invasive screening option, it may help improve early detection rates and ultimately save lives. However, regular colonoscopies remain the gold standard for accuracy and early intervention.