FDA Weighs Blood Test for Colon Cancer Screening

FDA Weighs Blood Test for Colon Cancer Screening
FDA Weighs Blood Test for Colon Cancer Screening. Credit | stock.adobe

United States – An advisory panel of the US FDA endorsed the new blood-based colorectal cancer screening test on Thursday.

With a 7-2 majority, it determined that using Guardant Health’s Shield test for colon cancer carries more risk than reward.

Potential Impact on Screening Rates

“The advisory committee’s strong support for the approval of Shield reinforces the crucial role that a blood test option can have in improving [colon cancer] screening rates for those at average risk,” Guardant co-CEO AmirAli Talasaz said in a company news release announcing the panel vote, as reported by HealthDay.

“Despite the importance of detecting colorectal cancer early, there are notable barriers that can deter average-risk Americans from completing existing screening methods,” Talasaz added. “Shield effectively detects cancer at an early stage when it is most treatable. Providing people with this blood test alongside other noninvasive stool tests can increase the rate of colorectal screening and potentially reduce preventable [colon cancer] deaths.”

Current Landscape and Challenges

If approved by the FDA, Shield would become the second blood-based colon cancer test in the United States: Currently, the only global regulatory approval for an epigenetic-based colon cancer screening test has been given to Epigenomics’ Epi proColon in September 2016.

An estimation is that about 150,000 persons in the U.S. are diagnosed with colon cancer each year and it ranks second to lung cancer as the leading cause of death and cancer with more than Fifty thousand deaths annually as per the American Cancer Society.

Current Landscape and Challenges

At this particular moment, colonoscopy is widely employed for the diagnosis of colon cancer. Still, test compliance is low since it involves invasion into the colon, and preparation for the test is bulky. Other tests include fecal tests such as Exact Sciences’ Cologuard, but blood-based tests are considered more convenient, NBC News reported.

Precision and Efficacy Concerns

Discussants noted that Guardant’s test was less precise than colonoscopy, particularly as Shield identified only 13 percent of other early-stage growths referred to as advanced adenomas, as NBC News pointed out. The FDA staff also raised this issue in briefing documents.

Guardant claimed that a specific research issued for approval revealed that the test identified 83% of colon cancers, FDA documents showed.

Shield “It is better than nothing, but I do not want to minimize the problem that is going to miss a lot of cancers,” as panel member Charity Morgan, a professor at the University of Alabama Department of Biostatistics, stated during the panel, according to NBC News, as reported by HealthDay.

Future Implications and Recommendations

Taking the floor at the meeting recently, Guardant Health’s Victoria Raymond stated that ‘This test must be repeated once, at least, every one to three years,’ NBC News reported, but ‘colonoscopy should remain the prioritized option.’