FDA Approves Shield Blood Test for Colon Cancer Detection

The U.S. Food and Drug Administration (FDA) has recently approved a new test for colon cancer detection. This test is known as Shield blood test and is the second test that is approved by FDA. The first test is Epigenomics’ Epi proColon that was approved in 2016. The FDA advisory panel voted 7-2 in favor of the Guardant Health’s Shield blood test’s benefits. 

Guardant has announced that Shield is the first FDA-approved blood test for primary colorectal cancer screening. It allows healthcare providers to offer it similarly to other noninvasive methods recommended in screening guidelines. Additionally, Shield meets Medicare coverage requirements and that makes it the first blood test for colorectal cancer screening. 

Experts said that blood tests for colon cancer are expected to increase screening rates for the disease, which is the second leading cause of cancer-related deaths in the United States. The American Cancer Society predicts that around 107,000 cases of colon cancer will be diagnosed this year, resulting in over 46,000 deaths. 

Shield blood test is a new solution to the persistent gap in colorectal cancer screening rates. The FDA’s decision will make blood-based testing and CRC screening more accessible and potentially save many lives. 

One of the reputed gastroenterologists, Dr. Daniel Chung, believes that increased screening rates and early cancer detection will lead to a new era of cancer screening. 

Coloscopy is the gold standard test for colon cancer. But adherence is low due to its invasive nature and daunting preparation. Other tests include fecal tests like Cologuard. But blood-based tests are more convenient than that. 

Panelists expressed concerns about the accuracy of Guardant’s test, particularly Shield as it only detected 13% of advanced adenomas. It is a concern that was also raised by FDA staff in briefing documents. 

The FDA has stated in its documents that Guardant’s application for approval was supported by a study that demonstrated the test effectively detects 83% of colon cancers.  

Shield is a screening test designed for individuals at average risk for colorectal cancer aged 45 or older. It cannot detect high-risk individuals. A positive blood test results raise concern for colorectal cancer or advanced adenoma. Hence those patients should be referred for colonoscopy evaluation.  

But panel member Charity Morgan, said that Shield is better than nothing, but it cannot detect many cancers and this test is only effective for individuals aged 45 or older.