Circulating tumor cells versus circulating tumor DNA in lung cancer-which one will win?

Abstract

Liquid biopsies appear to be a reliable alternative to conventional biopsies that can provide both precise molecular data useful for improving the clinical management of lung cancer patients as well as a less invasive way of monitoring tumor behavior. These advances are supported by important biotechnological developments in the fields of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). Analysis of CTCs and ctDNA may be useful in treatment selection, for response monitoring, and in studying resistance mechanisms. This review focuses on the most recent technological achievements and the most relevant clinical applications for lung cancer patients in the CTC and ctDNA fields, highlighting those that are already (or are close to) being implemented in daily clinical practice.

Keywords: Lung cancer, circulating tumor cell (CTC); biomarker; circulating tumor DNA (ctDNA); liquid biopsy.

Figure 1

The potential clinical benefits of CTC and ctDNA analyses in cancer care. CTC, circulating tumor cell; cfDNA, circulating free DNA; CTM, circulating tumor microemboli.

Figure 2

Comparison of the analysis capability and the technologies available for CTCs and ctDNA. CTC, circulating tumor cell; cfDNA, circulating free DNA; NGS, next generation sequencing; RTqPCR, real-time quantitative PCR; FISH, fluorescence in situ hybridization.