Liquid biopsy in colorectal cancer: No longer young, but not yet old

Abstract

Colorectal cancer (CRC) is one of the most prevalent cancers and the second leading cause of cancer-related deaths worldwide. The treatment strategy employed in CRC patients is becoming highly dependent on molecular characteristics present at diagnosis and during treatment. Liquid biopsy is an emerging field in the management of this cancer, and its relevance as a potential diagnostic, prognostic, monitoring, and therapeutic tool makes it a viable strategy in the clinical management of CRC patients. Liquid biopsy also has certain limitations, but these limitations seem to be at the reach of near-future technological development. In this letter, we focus on the clinical perspectives of liquid biopsy in CRC with particular regard to the various biomarkers recently identified that have been shown to be potentially useful in multiple aspects of early stage or metastatic CRC.

Keywords: Colorectal cancer; Liquid biopsy; Circulating tumor DNA; Diagnosis; Prognosis; Targeted therapy

Core Tip: Liquid biopsy through analysis of biological components, such as circulating nuclear acids, circulating tumor cells, and more recently exosomes in body fluids, has shown good capacity to overcome several limitations faced by conventional tissue biopsies, in particular invasiveness and unrepeatability. Liquid biopsy has shown significant results in clinical applications in different types of cancer, especially colorectal cancer (CRC). Indeed, liquid biopsy can be used to detect CRC at an early stage, make treatment decisions, monitor response to treatment, predict relapses and metastases, reveal tumor heterogeneity, and detect minimal residual disease.