New non-invasive approaches that can complement and improve on current strategies for colorectal cancer (CRC) screening and management are urgently needed. A growing number of publications have documented that components of tumors, which are shed into the circulation, can be detected in the form of liquid biopsies and can be used to detect CRC at early stages, to predict response to certain therapies and to detect CRC recurrence in a minimally invasive way. The analysis of circulating tumor DNA (ctDNA), tumor-derived cells (CTC, circulating tumor cells) or circulating microRNA (miRNA) in blood and other body fluids, have a great potential to improve different aspects of CRC management. The challenge now is to find which types of components, biofluids and detection methods would be the most suitable to be applied in the different steps of CRC detection and treatment. This chapter will provide an up to date review on ctDNA, CTCs and circulating miRNAs as new biomarkers for CRC, either for clinical management or early detection, highlighting their advantages and limitations.

迫切需要能够补充和改善当前大肠癌（CRC）筛查和管理策略的新的非侵入性方法。越来越多的出版物记录了脱落到循环中的肿瘤成分可以以液体活检的形式进行检测，并且可以用于早期检测CRC，预测对某些疗法的反应以及检测CRC复发。以微创的方式。血液和其他体液中循环肿瘤DNA（ctDNA），肿瘤来源细胞（CTC，循环肿瘤细胞）或循环microRNA（miRNA）的分析在改善CRC管理的各个方面均具有巨大潜力。现在的挑战是要找到哪种类型的组件，生物流体和检测方法将最适合应用于CRC检测和治疗的不同步骤。本章将就ctDNA，CTC和循环miRNA作为CRC的新生物标志物提供最新的综述，以用于临床管理或早期发现，强调其优势和局限性。