CtDNA and colorectal cancer

A tumor can release cancer cells, extracellular vesicles, proteins and nucleic acids into the bloodstream. These substances have considerable potential as diagnostic or theranostic biomarkers. Circulating tumor DNA (ctDNA) has attracted growing interest in recent years, particularly in colorectal cancer (CRC) research. ctDNA could have several clinical applications in the near future, such as early tumor detection (screening and diagnosis), molecular profiling (mainly for prognostic and theranostic purposes) and therapeutic decision support in adjuvant (search for minimal residual disease (MRD)) and metastatic (initial and dynamic measurement of ctDNA to predict therapeutic efficacy) settings. One of the main advantages of tcDNA is its ability to provide a fine, dynamic description of tumour mass and composition, compared with tissue biopsy (sampling bias) or conventional tumour markers whose sensitivity and specificity are not optimal. Thus, recent scientific studies on the performance of tcDNA in these different areas of clinical application are overturning concepts of CRC management.
In this lecture, we will discuss the origin of tcDNA, the technologies enabling its detection, the concept of MRM and the value of tcDNA in the adjuvant setting. Finally, we will briefly summarize other clinical applications of tcDNA in the detection and treatment of metastatic CRC.