[Analysis of liquid biopsies for cancer diagnosis: Systematic review]

The incidence of cancer has increased in recent years, especially in those over 65 years of age, posing a major health problem. Many tumours have a poor prognosis because they are diagnosed at very advanced stages. It is therefore especially important to incorporate liquid biopsy into clinical practice as a method for detecting tumours at very early stages. A systematic review was conducted, with the main objective of analysing the available literature on the use of liquid biopsy in the early diagnosis of cancer, and as a secondary objective, to determine the types of tumours that can be diagnosed early by liquid biopsy and the available biomarkers. The results indicate a lack of agreement with the biomarkers detected and the technologies applied. This highlights the need for multicentre studies to look at large cohorts and to establish protocols of action, as well as to increase analytical validity and the possibility of using a screening test for each type of tumour. This could be a very important step forward, as it could improve the management of cancer patients to a great extent.