FDA approves blood test method for colon cancer screening – Times of India

The Food and Drug Administration (FDA) on Monday approved Guardant Health’s Shield blood test for colon cancer screening.
Although it doesn’t replace colonoscopies, doctors are optimistic it might improve screening rates for the second-highest cause of cancer death in the US, according to NBC News.
Shield had been available for $895, but FDA approval means Medicare and private insurers will likely cover it, making it more accessible.
Dr. Arvind Dasari from the University of Texas MD Anderson Cancer Center called the approval a “welcome development,” but cautioned, “we’ll have to wait and see what the impact will be in terms of improving screening and reducing the incidence of mortality.”
The American Cancer Society estimates that over 53,000 people will die from colorectal cancer this year. Research in March showed Shield is 83% effective at detecting colorectal cancers by identifying cancerous DNA in the bloodstream. It is most effective at detecting later-stage cancers, but only found 13% of earlier-stage polyps. The test should be administered every three years starting at age 45, the recommended age for colorectal screening.
A positive Shield test isn’t a diagnosis. Patients still need a colonoscopy to locate and assess the progression of tumors. “People have to understand that a positive Shield test requires a colonoscopy to confirm that you have an advanced lesion or colorectal cancer, or that the results were false,” said Robert Smith, senior vice president of Early Cancer Detection Science at the American Cancer Society. “A test like this is not complete if it’s positive and you have not had a colonoscopy.”
This is the second blood test for colon cancer screening; the first, Epigenomics’ Epi proColon, was approved in 2016 but is rarely used due to concerns about its accuracy. It is not covered by Medicare or private insurance.
Since the mid-1990s, colon cancer rates in people under 55 have been rising by 1% to 2% each year, while cases and deaths among those 60 and older have been declining, according to the American Cancer Society.
“What breaks my heart is that it’s preventable,” said Dr. William Grady, a gastroenterologist at Fred Hutchinson Cancer Center in Seattle. “One of my biggest joys is when I’m doing colonoscopy and I can take out polyps” that would have progressed to cancer if left untreated.
Colorectal cancer can be prevented with screening, and colonoscopy is the most accurate way to detect it. However, fewer than 60% of eligible people undergo recommended screening.
“The biggest problem with colon cancer right now is that there’s a significant part of the population that’s not getting screened,” said Dr. Sapna Syngal of the Dana-Farber Cancer Center in Boston. “If this test increases the number of people getting screened, it’s going to have a huge impact.”
Grady, who led the Shield test study, noted that adults in their 40s and 50s are least likely to comply with screening due to work and family responsibilities. “These are people who are employed, many have families, and so you have all of these other life responsibilities that get in the way of taking care of themselves,” he said.
“Many people don’t like the messiness of dealing with stool, and many people really don’t like the colonoscopy — mostly the prep,” said Electra Paskett from the Ohio State University Comprehensive Cancer Center. “I think a blood test would be ideal for many people.”
Other screening methods include fecal occult blood tests to detect blood in stool and FIT-DNA tests like Cologuard, effective at detecting cancer but less so for precancerous polyps.