Technical considerations for circulating tumor DNA detection in oncology

ABSTRACT

Introduction: Blood draw or collection of other body fluids, known as ‘liquid biopsies’ are generally less invasive procedures than tumor biopsies. Cell-free tumor DNA (ctDNA) is widely evaluated in cancer for early detection, diagnosis, prognosis, therapy monitoring or determination of minimal residual disease. In body fluid samples, ctDNA can represent a small fraction of total cell-free DNA (cfDNA), requiring highly sensitive assays.

Areas covered: The first part of this review is dedicated to critical preanalytical points necessary to obtain suitable samples for cfDNA analysis. The second part describes the available techniques for ctDNA analysis.

Expert commentary: Detection of ctDNA is emerging as a powerful adjunct in the management of patients with cancer. For reliable ctDNA detection, preanalytical steps from sampling to DNA extraction are crucial. Various techniques are available for cfDNA detection, but one needs to consider the appropriate application for the patient’s clinical trajectory, whether it is for diagnosis or disease monitoring. Broad screening assays like Next-Generation Sequencing should be used for early cancer detection or for tumor molecular characterization to guide therapy options in a molecular board context. Techniques designed for unique hotspot or well-identified mutations are the most sensitive and should be used for monitoring purposes.

KEYWORDS:

• Circulating tumor DNA
• liquid biopsy
• preanalyticial
• polymerase chain reaction
• next-generation sequencing
• mass spectrometry

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewers Disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper was not funded.