New Blood Test Offers Option for Colorectal Cancer Screening

Guardant Health, Inc., has announced that the U.S. Food and Drug Administration (FDA) has approved the company’s Shield™ blood test for colorectal cancer screening. This approval marks a significant milestone, as Shield is the first blood test approved by the FDA as a primary screening option for colorectal cancer. 

Dr. Michael Kaczanowski, a board-certified gastroenterologist at Foundation Gastroenterology, says, “I welcome the advancements in colorectal cancer screening, including the new circulating cell-free DNA (cfDNA) blood test. This test offers a promising non-invasive option, with studies showing a sensitivity of around 85% for detecting colorectal cancer, which is comparable to other non-invasive screening methods. However, it's essential to highlight that this test, like stool-based tests, focuses on detecting cancer that may already be present. Colonoscopy remains the gold standard for detecting colon cancer before it begins or in its earliest stages.” 

The Critical Importance of Colon Cancer Screening  

Colorectal cancer is the second-leading cause of cancer-related deaths in the U.S., despite being highly treatable when detected early. The American Cancer Society estimates that over 150,000 people will be diagnosed with colorectal cancer in 2024, with more than 53,000 deaths expected from the disease.  

Early detection is crucial, as the five-year relative survival rate for early-stage colon cancer is 91%, compared to just 14% for cancer that has spread to distant parts of the body. 

Currently, the colorectal screening rate in the U.S. is about 59% for eligible individuals. More than 50 million eligible Americans do not complete  screening, often due to the perceived inconvenient nature of existing screening methods like colonoscopy or stool-based tests. 

The introduction of the Shield test offers an appealing alternative. This blood test can be completed with a simple blood draw during a routine primary care office visit. 

Why Colonoscopy Is Still Necessary 

The advantage of a colonoscopy lies in its ability to prevent colorectal cancer. Dr. Kaczanowski explains, “Colonoscopy allows us not only to detect cancer but also to directly visualize and remove precancerous polyps, effectively stopping cancer before it begins. This preventive aspect is something that cfDNA tests and other non-invasive options simply cannot provide.” 

Dr. Kaczanowski continued, “Both the American College of Gastroenterology and the American Gastroenterological Association emphasize the importance of colonoscopy as the most effective tool for both detection and prevention. While they recognize the value of emerging technologies like cfDNA testing for patients who may be unable to undergo colonoscopy, they continue to recommend colonoscopy as the preferred method for comprehensive colorectal cancer screening.  

“By identifying and removing polyps before they turn into cancer, we can truly make a difference in reducing colorectal cancer incidence,” concluded Dr. Kaczanowski. 

Talk to your doctor about which colon cancer screening option is right for you. Colorectal cancer screening saves lives.