Liquid biopsy for cancer - an update on a rapidly changing field.
Speaker: Professor Stefanie Jeffrey - Stanford University, Stanford, United States
Abstract: Liquid biopsy refers to assays that measure or characterize cancer-associated cells, nucleic acids, extracellular vesicles (EVs), and other tumor-related or ‘tumor-educated’ components found blood or other body fluids, such as urine, saliva, and tears. As it is minimally invasive, liquid biopsy may be performed serially to detect changes that may appear over time during cancer treatment and evolution. The analyses of tumor-associated cells and/or products are also being combined with measurements of other tumor-associated proteins and blood biomarkers or concurrent imaging measurements to develop broader marker constructions.
Focusing on circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), liquid biopsy assays are in use or under investigation in three areas:
- prognosis, drug selection, and monitoring of treatment response in advanced disease;
- surveillance for micrometastatic disease after curative-intent therapy for primary non-metastatic cancer, including ‘ctDNA relapse’, a term we recently introduced for tumor recurrence revealed by ctDNA detection prior to imaging-detected relapse;
- screening and early detection of cancer in asymptomatic or high-risk populations or in individuals with imaging or other test abnormalities.
Other aspects of liquid biopsy to be discussed include clonal hematopoiesis of indeterminate potential (CHIP) that may confound ctDNA analyses, the matching of druggable genetic aberrations to specific therapies, and limitations that need to be addressed prior to implementation of liquid biopsy into everyday clinical practice.