Recent research reveals that a novel at-home blood test for colorectal cancer could be as effective as existing stool sample tests. Medical professionals are optimistic that this easier test might encourage more people to screen for colorectal cancer early, though colonoscopy remains the gold standard for detection. The at-home stool test, while not particularly pleasant, now faces competition from this new blood test, which has shown about 83% accuracy, comparable to stool tests, as per findings in the New England Journal of Medicine.
These results, pertinent to average-risk, asymptomatic individuals, still fall short of the accuracy of colonoscopies. Dr. William Grady of Fred Hutchinson Cancer Center in Seattle, involved in the study, sees this development as a significant step in creating accessible detection methods for early-stage colorectal cancer. The ECLIPSE study, a large-scale trial, compared the effectiveness of colonoscopies and the Guardant’s Shield blood test, which identifies colorectal cancer signals in blood DNA, known as circulating tumor DNA (ctDNA).
In the study, 83% of people with colonoscopy-confirmed colorectal cancer tested positive for ctDNA, while 17% tested negative. The blood test proved most effective for detecting colorectal cancers, including early-stage ones, but less so for advanced precancerous lesions.
Colorectal cancer, a leading cause of cancer deaths in the U.S., has seen declining death rates in older adults but increasing rates in individuals under 55. Current guidelines suggest screening beginning at age 45 for those at average risk. Dr. Grady emphasizes the importance of a blood-based test during routine doctor visits, especially for younger demographics increasingly affected by this cancer.
Dr. Jeremy Kortmansky of Yale Cancer Center notes the challenge in achieving higher accuracy with home-based tests due to the variable DNA shedding from lesions of different sizes. He also acknowledges the reluctance to perform home-based stool tests, partly due to their unpleasant nature and the necessity for a prescription.
Dr. Anton Bilchik, from Providence Saint John’s Cancer Institute, remarks on the increasing incidence of colorectal cancer in younger individuals. He links this trend to changes in the microbiome and highlights the potential of this study in understanding the bacterial factors in colorectal cancer development and prevention. This research could also inform future therapeutic targets.
Kortmansky points out indicators of colorectal cancer, such as abdominal pain, changes in bowel habits, blood in stool, weight loss, and low iron levels, stressing the importance of early detection when the disease is asymptomatic and more treatable.