Circulating Tumor DNA in KRAS positive colorectal cancer patients as a prognostic factor - a systematic review and meta-analysis

Background: Liquid biopsy is a novel tool in oncology. It provides minimally invasive detection of tumor specific DNA. This review summarizes data on presence of circulating tumor DNA in serum or plasma of CRC patients as a potential negative prognostic factor. Materials and Methods: The systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The search was performed using PubMed, Web of Science and Scopus. Results: In total 18 articles with a total of 1779 patients ma the inclusion criteria. Six out of 8 studies found that presence of ctDNA in plasma/serum was associated with inferior overall survival. All 6 studies found that high concentrations of ctDNA in plasma/serum was associated with inferior overall survival. Conclusions: Presence or high concentrations of KRAS mutation in plasma or serum were associated with inferior prognosis. Establishing cut-off concentrations is warranted for further clinical implementation of liquid biopsy.