Clinical Validation of a Circulating Tumor DNA-Based Blood Test to Screen for Colorectal Cancer

Area of Science:

• Oncology
• Molecular Diagnostics
• Preventive Medicine

Background:

• Colorectal cancer (CRC) screening is crucial but underutilized.
• Blood-based screening tests offer potential for improved adherence over traditional methods.
• Clinical validation of blood-based CRC tests in screening populations is essential.

Purpose of the Study:

• To assess the clinical performance of an investigational blood-based circulating tumor DNA (ctDNA) test for CRC detection.
• To evaluate the test's accuracy in an average-risk screening population using colonoscopy and histopathology as the reference standard.

Main Methods:

• A prospective, multicenter, cross-sectional observational study.
• Enrolled 27,010 asymptomatic adults aged 45-85 at average risk for CRC.
• Participants underwent blood collection for the ctDNA test followed by a screening colonoscopy; all parties were blinded to results.

Main Results:

• The blood test demonstrated a sensitivity of 79.2% for CRC and a specificity of 91.5% for advanced colorectal neoplasia.
• Negative predictive value for advanced colorectal neoplasia was 90.8%, with a positive predictive value of 15.5%.
• Sensitivity for advanced precancerous lesions was 12.5%, falling short of acceptance criteria.

Conclusions:

• The blood-based ctDNA test shows acceptable accuracy for detecting colorectal cancer in an average-risk screening population.
• The test's ability to detect advanced precancerous lesions requires improvement.
• Further research and development are necessary to enhance the test's sensitivity for precancerous conditions.