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Updated: Apr 1, 2026
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Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids
Published on: June 8, 2019
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Blood-Based Circulating Tumor DNA for Early Detection of Colorectal Cancer: A Systematic Review and Meta-Analysis
Yashaswi Guntupalli1, Rithish Nimmagadda2, Vineeth Potluri3
1Department of Internal Medicine, Sri Venkateswara Institute of Medical Sciences, Tirupati, India.
Digestive Diseases (Basel, Switzerland)
|March 30, 2026
Summary
Blood tests using circulating tumor DNA (ctDNA) show high accuracy for detecting colorectal cancer (CRC) in asymptomatic adults. While sensitive and specific, their predictive value in screening settings requires further investigation.
Area of Science:
- Oncology
- Molecular Diagnostics
- Cancer Screening
Background:
- Colorectal cancer (CRC) screening is crucial for early detection and improved outcomes.
- Non-invasive biomarkers are needed to enhance screening strategies.
- Circulating tumor DNA (ctDNA) assays are emerging as promising blood-based tools for cancer detection.
Purpose of the Study:
- To systematically review and meta-analyze the diagnostic accuracy of blood-based ctDNA assays for early CRC detection in asymptomatic individuals.
- To evaluate ctDNA assays (mutation, methylation, fragment-based) against established diagnostic standards.
Main Methods:
- Systematic review and meta-analysis of prospective and cross-sectional diagnostic accuracy studies.
- Inclusion of studies comparing ctDNA assays to colonoscopy or histopathology.
- Calculation of pooled sensitivity, specificity, and other diagnostic metrics using a bivariate random-effects model.
- Assessment of risk of bias (QUADAS-2) and certainty of evidence (GRADE).
Main Results:
- Nine studies contributed to pooled estimates, showing high diagnostic accuracy.
- Pooled sensitivity: 0.887 (95% CI, 0.848-0.920); Pooled specificity: 0.913 (95% CI, 0.898-0.928).
- Excellent discrimination indicated by an AUC of 0.97.
- High negative predictive value (>99%) but low positive predictive value (<20%) at typical screening prevalences.
- No significant differences in accuracy observed across different ctDNA assay types.
Conclusions:
- Blood-based ctDNA assays demonstrate high sensitivity, specificity, and discriminative ability for CRC detection.
- Limited predictive value at low screening prevalences and study heterogeneity are challenges for clinical adoption.
- Further large-scale, standardized, population-based studies are necessary to validate and optimize ctDNA assays for CRC screening.
