Liquid Biopsy and Multi-Cancer Early Detection Tests for Cancer Screening: A Scoping Review.

Liquid biopsy constitutes a range of tests that use biological fluids to detect cancer. Research is now targeting their use for cancer screening. This is the first review of the evidence on liquid biopsy tests across a range of analytical parameters, biomarkers, and cancer types for cancer screening. A scoping review was conducted using JBI methodology for scoping reviews. MEDLINE and targeted websites were searched for studies published in 2014 or later on the use of liquid biopsy and multi-cancer early detection tests for screening. A total of 104 studies were included, covering a wide range of study designs. Several types of biomarkers (e.g., cell-free DNA, circulating tumor DNA) and analytical parameters were used. Most studies addressed test performance outcomes, while fewer addressed clinical outcomes, implementation considerations, and cost-effectiveness. No empirical studies on cancer-specific mortality were found. A large body of literature was identified that covered a range of cancer types, biomarkers, analytical parameters, and outcomes. Critical gaps in the literature were demonstrated, including evidence on clinical outcomes such as cancer-specific mortality and potential harms that currently preclude the implementation of liquid biopsy tests for cancer screening. Findings of this review can be used to guide the necessary future research.