The study compared two different types of tests used for screening colorectal cancer: a non-invasive, multitarget stool test that includes DNA markers related to colon cancer along with a test that detects stool blood, versus a commercial fecal immunochemical test (FIT). While the FIT test detects hidden blood in the stool, a potential signal for cancer, the multitarget test also includes genetic mutations in the stool that are related to cancer. In the study of nearly 10,000 participants, the DNA test detected 92 percent of colon cancer, significantly more cancers compared to the 72 percent for the FIT test in asymptomatic participants at average risk for colorectal cancer.
The results from this study could impact screening rates, which remain frustratingly low in the U.S. despite the evidence of their effectiveness.
“Detection of 92 percent of colon cancer is extremely high for a non-invasive test, so that a negative test result means that no further evaluation, like colonoscopy, is needed at that time,” said Ransohoff. “Having such a sensitive, non-invasive option could have an important effect on screening rates for colorectal cancer.”
While the DNA test appears to be more sensitive than the FIT test, it did produce more false positive results, which would lead to colonoscopy. Further, the study did not address the question of how frequently non-invasive testing might be needed.
Colorectal cancer is the third leading cause of cancer-related deaths in the United States and is expected to cause over 50,000 deaths in 2014, according to the American Cancer Society.