Circulating free DNA in head and neck cancer – a systematic review

Introduction: Liquid biopsy becomes usefulness in many types of cancers. Cell free DNA (CfDNA) contains DNA released physiologically and pathologically from cells to body fluids. Liquid biopsy allows to search and evaluate DNA in blood, saliva, urine etc. Development of this method can provide more precise, personalisation of oncological therapy. Head and neck cancers (HNC) are responsible for 350 000 deaths yearly worldwide. Head and neck squamous cell carcinoma (HNSCC) is most common HNC type-about 90% cases. HNSCC is often diagnosed in advanced disease stages what is associated with poor survival. Aim: The intention of this systematic review was to compare papers which used liquid biopsy of circulating free DNA in detection and therapy of head and neck cancers. Methods: Articles from last 7 years in Pubmed and Google Scholar base were searched. Results: We found 16 articles fulfilling criteria. Discussion: Level of CfDNA depends of cancer occurrence, its advancements. The higher the stage of the disease, the higher the levels of CfDNA and tumor DNA in it. Detectable CfDNA after chemo or radiotherapy may predict recurrence, Heterogeneity of HNC was demonstrated, bigger than other cancers. Alternations in TP53 and PIK3CA were most common through included studies. Human Papillomavirus DNA disclosure in CfDNA have valuable specificity and show similar properties as tumor DNA. Studies showed that saliva is equally good material in liquid biopsy as a blood, especially in oral cancers. Conclusion: Results are promising but showed limitations. Future research should be more standardized, include more cases and compare treatments methods.