Laura Bonanno, MD, Veneto Institute of Oncology, Padova, Italy, explains the way in which liquid biopsies can be used to detect genetic alterations. She explains how liquid biopsies are a cost-effective, repeatable form of biopsy, which can be used to monitor tumors during treatment to anticipate progression and tailor treatment to the patient. This video was recorded at the European Lung Cancer Congress (ELCC) 2019, held in Geneva, Switzerland.