The cfDNA blood test had 83% sensitivity for CRC, 90% specificity for advanced neoplasia, and 13% sensitivity for advanced precancerous lesions. Other noninvasive screening methods have sensitivity from 67% to 94% for CRC and 22% to 43% for advanced precancerous lesions.
The cfDNA blood test identified 42 of 48 stage I, II, or III CRCs, indicating a sensitivity of 87.5%, including 65% for stage I cancers, 100% for stage II cancers, and 100% for stage III cancers. The test also identified all 10 of the stage IV CRC cases. There were no substantial differences in sensitivity for CRC based on primary tumor location, tumor histologic grade, or demographic characteristics.
Among 1116 participants with advanced precancerous lesions identified as the most advanced lesion on colonoscopy, the cfDNA blood test was positive for 147, indicating a sensitivity for advanced precancerous lesions of 13.2%. Melson, who wasn't involved with this study, noted that blood-based testing shows promise for cancer detection but needs additional support for real-world implementation. For instance, the Shield blood test has difficulty detecting precancerous lesions, and it remains unclear what the optimal intervals for repeat testing would be after a negative test, he said. In addition, screening programs will need to ensure they have capacity to effectively deal with a positive test result.