A recent study published on Wednesday showcased promising results for a blood test aimed at detecting colon cancer, offering a potential new avenue for screening against one of the leading causes of cancer-related deaths.
The innovative test targets DNA fragments released by tumor cells and precancerous lesions. While already available for purchase in the U.S. at $895, it awaits approval from the Food and Drug Administration (FDA), with limited coverage by insurers. Guardant Health, the test’s manufacturer, anticipates an FDA decision later this year.
In the study, the blood test successfully identified 83% of colon cancers, although it detected very few precancerous growths compared to colonoscopies, which remain the gold standard for colon cancer screening. While colonoscopies not only detect tumors but also prevent the disease by removing precancerous polyps, many individuals are deterred by the inconvenience of the procedure, including time off work and rigorous bowel preparation.
Offering a convenient alternative, annual stool tests allow individuals to send samples to a lab for analysis. Dr. Douglas Corley of Kaiser Permanente emphasized the importance of providing choices in screening methods to improve overall participation rates.
Despite recommendations for screening in healthy adults aged 45 to 75, current screening rates fall short of targets set by health organizations. Guardant Health recommends its blood test, named Shield, every three years, with follow-up colonoscopies required for abnormal results.
The study, sponsored by Guardant and published in the New England Journal of Medicine, involved over 7,800 participants who underwent both colonoscopies and blood tests. While the blood test detected 83% of colon cancers, it missed 17%, comparable to stool-based tests.
However, false alarms were noted, with the blood test falsely suggesting colon cancer in 10% of cases where colonoscopies revealed no abnormalities, potentially causing anxiety and additional procedures.
Further research is needed to ascertain the test’s specificity and its potential to detect other cancers, according to Dr. Corley.
Colon cancer ranks as the second leading cause of cancer deaths in the U.S. and the third worldwide, underscoring the urgency for effective screening methods. Dr. William Grady of the Fred Hutchinson Cancer Center highlighted the potential impact of increased screening on reducing cancer-related deaths.
In a related study, an updated version of the Cologuard stool test, which also identifies DNA fragments, demonstrated improved performance in minimizing false alarms, offering hope for more efficient screening methods.
Dr. Nabil Mansour of Baylor College of Medicine welcomed the addition of blood tests as a screening option, emphasizing the importance of providing patients with diverse choices to enhance screening accessibility and effectiveness.
Gary P Hernal started college at UP Diliman and received his BA in Economics from San Sebastian College, Manila, and Masters in Information Systems Management from Keller Graduate School of Management of DeVry University in Oak Brook, IL. He has 25 years of copy editing and management experience at Thomson West, a subsidiary of Thomson Reuters.
