Increasing evidence suggests that targeted sequencing of cell free DNA (cfDNA) can provide a comprehensive molecular portrait of solid tumors. However, the concordance between tissue and cfDNA next generation sequencing (NGS) testing is usually low. This phenomenon might be due to different factors, including sequencing artifacts, clonal hematopoiesis and/or tumor heterogeneity. Therefore, appropriate internal and external validation of NGS methods are required before their use in the clinical scenario. Nevertheless, cfDNA testing can provide information that is complementary to tissue testing and that can aid to personalize treatments in patients with metastatic tumors. In addition, cfDNA testing might allow monitoring response to treatments and identifying mechanisms of acquired resistance that offer opportunity for therapeutic intervention. Results of liquid biopsy testing with NGS should be discussed in the Molecular Tumor Board to guarantee their appropriate interpretation and integration in the clinical scenario.

Learning Objectives:

1. Acquire knowledge on the limits and potential of cfDNA testing in solid tumors

2. Understand how to use cfDNA testing in clinical research