Nowadays, analyzing
circulating tumor DNA (ctDNA), a very small part of circulating free
DNA (
cfDNA) carried by blood, is considered to be an interesting alternative to conventional single-site
tumor tissue biopsies, both to assess
tumor burden and provide a more comprehensive snapshot of the time-related and spatial heterogeneity of
cancer genetic/epigenetic scenery. The determination of ctDNA and/or mapping its characteristic features, including
tumor-specific mutations,
chromosomal aberrations, microsatellite alterations, and epigenetic changes, are minimally invasive, powerful and credible
biomarkers for early diagnosis, follow-up, prediction of
therapy response/resistance, relapse monitoring, and tracking the rise of new mutant subclones, leading to improved
cancer outcomes This review provides an outline of advances published in the last five years in electrochemical biosensing of ctDNA and
surrogate markers. It emphasizes those strategies that have been successfully applied to real clinical samples. It highlights the unique opportunities they offer to shift the focus of
cancer patient management methods from actual decision making, based on clinic-pathological features, to
biomarker-driven treatment strategies, based on genotypes and customized targeted
therapies. Also highlighted are the unmet hurdles and future key points to guide these devices in the development of liquid biopsy cornerstone tools in routine clinical practice for the diagnosis, prognosis, and
therapy response monitoring in
cancer patients.