Liquid biopsy and ctdna analysis in colorectal cancer: role in assessing minimal residual disease and personalizing therapy. A literature review

Colorectal cancer, which remains one of the most common malignancies with a high mortality rate, is characterized 
by significant clinical and biological heterogeneity. Traditional approaches to risk stratification and treatment response 
assessment based on disease stage and imaging data are often insufficient to accurately predict the individual course of the 
disease and early detection of relapses. In recent years, liquid biopsy technology, a key element of which is the analysis of 
circulating tumor DNA (ctDNA), has become a part of the clinician’s arsenal. This review analyzes the role of this technology 
in the context of modern oncology. It examines in detail the biological basis of this method, its key role in detecting minimal 
residual disease after radical treatment, and reconsidering approaches to adjuvant therapy. Particular attention is paid to 
the possibilities of dynamically monitoring the effectiveness of systemic treatment in metastatic disease, tracking tumor 
clonal evolution, and assessing drug resistance mechanisms. Technological aspects, as well as organizational and economic 
prospects for integrating the method into algorithms for multidisciplinary management of patients with colorectal cancer 
are discussed.