Circulating Tumor DNA Detection and Clinical Applications

Detection Technologies

The European Society of Medical Oncology recommends two main technological approaches for ctDNA detection: tumor-informed (customized panel) and tumor-agnostic (fixed panel), with the former providing highest sensitivity and accuracy but at greater cost, and the latter offering broader applicability at lower cost but with reduced sensitivity 1
Detection methods range from single-gene PCR assays to comprehensive next-generation sequencing (NGS) panels, including digital PCR, real-time PCR, and mass spectrometry-based platforms, as reported by the Neuro-Oncology journal 2, 3

The American Society of Clinical Oncology recommends ctDNA testing for EGFR mutation detection in non-small cell lung cancer (NSCLC), which is FDA-approved and predicts response to EGFR tyrosine kinase inhibitors, particularly useful when tissue is unavailable 4
The European Society for Medical Oncology recommends ctDNA testing for PIK3CA mutation testing in breast cancer, which is validated for selecting patients eligible for alpelisib therapy, with equivalent performance whether using tissue or liquid biopsy 5
The National Comprehensive Cancer Network recommends ctDNA testing for HER2 amplification and resistance mechanism detection in breast cancer, which is useful when tissue sampling is not feasible 4, 6

The American College of Pathology notes that sensitivity of ctDNA detection varies dramatically, depending on cancer stage, tumor burden, proximity of sampling site to disease, and biomarker type, with approximately 25% of NSCLC patients being "non-shedders" with DNA levels below detection limits 2, 4
The College of American Pathologists recommends that negative ctDNA test results require caution, as they do not exclude the presence of tumor mutations or amplifications and should never be considered definitive 4, 6

The European Liquid Biopsy Society emphasizes the importance of using only clinically validated ctDNA testing methods performed in CLIA-certified laboratories for clinical decision-making, with standardization remaining a critical challenge, particularly for NGS-based analyses 1, 3, 5, 10
The International Society for Liquid Biopsy Research recommends that interpretation and reporting of ctDNA results are more complex than conventional tissue-based NGS, requiring specific guidelines for optimal communication between laboratories and oncology teams 3, 10

The National Institute for Health and Care Excellence recommends that ctDNA is most appropriate when adequate tissue cannot be safely obtained or is insufficient for analysis, or when monitoring disease progression in patients unable to undergo repeat biopsies 4, 6
The American Society of Clinical Oncology recommends serial monitoring of ctDNA for treatment response or early recurrence detection, particularly in patients with metastatic disease 1, 6