Non-invasive blood assay can detect early CRC
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A novel, blood-based assay improved the detection of advanced and non-advanced adenomas by analyzing cell-free DNA and circulating gastrointestinal epithelial cells, according to research from Digestive Disease Week.
In a recorded audio presentation, Shai Friedland, MD, professor of medicine at the Stanford University Medical Center, said techniques to detect circulating cells in the blood have become more sensitive, which creates the potential to detect small adenoma earlier in their development in addition to larger adenomas and CRC.
“We have multiple good screening tests, but there are still many people out there who are not getting screened,” he said. “We’re hoping that by developing an effective and convenient blood test we can get more people screened and reduce mortality from colorectal cancer.”
Researchers evaluated the test, called FirstSight (CellMaX Life), in a single-center, blinded study conducted at the Veterans Affairs Palo Alto Health Care System. The study included 354 patients with no prior CRC diagnosis who were scheduled for colonoscopy. Among these patients, 86% were asymptomatic and 14% had symptoms or a positive fecal immunochemical test.
Prior to colonoscopy, investigators drew blood samples to be analyzed by the assay. Friedland said the test focuses on three biomarkers, circulating gastrointestinal epithelial cells, somatic mutations and methylation of cell-free DNA. Researchers developed a quantitative age- and sex- adjusted composite CMx Score from 0 to 100.
In their analysis, investigators determined that the test achieved a specificity of 90% and sensitivity of 100% and 76% for the detection of CRC and advanced adenomas, respectively. They also found an association between the CMx Score and disease severity (likelihood ratio P < .0001). The score also correlated with the size of the index adenomas.
The study included several patients who had elevated CMx Scores but had negative colonoscopies. After reviewing patient histories, researchers found a prior history of advanced adenoma removal in most cases. This knowledge revealed the potential to achieve an even higher specificity with the test, according to the study abstract.
“The blood test has the potential to fill an unmet need by giving patients a highly sensitive, convenient option for colorectal cancer screening,” Friedland said in his presentation. “We have continued to enroll patients at the Palo Alto VA to prospectively validate the blood test. The results will be available soon, and I can tell you they look extremely promising. The plan is to stay a large-scale, multicenter study soon.”
Reference:
Friedland S, et al. Abstract 575. Presented at: Digestive Disease Week; May 2-5, 2020; Chicago (meeting canceled).
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