FDA Approves Cutting-Edge Colon Cancer Test
On Monday, the U.S. Food and Drug Administration (FDA) granted approval for a new blood test designed to detect colon cancer.
Earlier in May, an FDA advisory committee had voted 7-2 in favor of the Guardant Health’s Shield test, determining that its benefits outweigh the potential risks for detecting colon cancer.
With this approval, Shield becomes the second blood test to receive FDA clearance for colon cancer detection, following Epigenomics’ Epi proColon, which was approved in 2016.
Guardant Health announced that Shield is the first blood test approved by the FDA as a primary screening tool for colorectal cancer, allowing healthcare providers to use it alongside other noninvasive screening methods recommended by guidelines. Additionally, Shield is the first blood test for colorectal cancer screening that qualifies for Medicare coverage.
Experts are optimistic that the introduction of blood tests for colon cancer will increase screening rates for this disease, which is the second leading cause of cancer-related deaths in the United States.
The American Cancer Society estimates that nearly 107,000 cases of colon cancer will be diagnosed this year, with over 46,000 deaths from the disease.
Dr. Daniel Chung, a gastroenterologist at Massachusetts General Hospital, commented on the approval, stating that the introduction of the Shield test represents a significant advancement in colorectal cancer screening. He believes it will enhance accessibility to screening and contribute to saving more lives through earlier detection.
Currently, colonoscopy is considered the gold standard for colon cancer detection, but its invasive nature and preparation requirements often lead to low adherence rates. Alternatives such as fecal tests, including Exact Sciences’ Cologuard, are available, but blood-based tests like Shield offer a more convenient option.
During the advisory panel’s review, concerns were raised about the accuracy of Guardant’s test, particularly its ability to detect pre-cancerous tumors, or advanced adenomas, which Shield identified only 13% of the time. This issue was also highlighted in the FDA’s briefing documents.
The approval of Shield was supported by a study showing that the test detected 83% of colon cancers. However, Guardant emphasized that Shield is intended for screening average-risk individuals aged 45 and older, not those at high risk for colorectal cancer. A positive result from Shield should be followed up with a colonoscopy for further evaluation.
Panel member Charity Morgan from the University of Alabama acknowledged the test’s limitations, noting that while it represents progress, it may still miss a significant number of cancers.
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