Liquid Biopsy in Cancer

As new Immune Checkpoint Inhibitors (ICI) are being studied in the medical field and used as new therapies to approach and battle cancer, many questions are left about their use: How much is enough? How many ICI therapies will someone need? How do we know it’s doing something?

Liquid biopsies are emerging as a rapid and accurate approach to monitoring tumor burden dynamics during immunotherapy. Liquid biopsies track the circulating cell-free tumor DNA (ctDNA) that serves as a biomarker, helping us understand the molecular wiring of therapeutic responses. It has also been shown to serve as a predictive and prognosis value. For liquid biopsies to work, you give a blood sample, then the blood cells are separated from the plasma, and the new technologies can detect Circulating Tumor Cells (CTC) or ctDNA in the plasma.

Using ctDNA to detect Minimal Residue Disease associated with micrometastatic disease before the development of metastases may guide a way to take advantage of the efficacy of immunotherapy for patients with early-stage disease. It can also help evaluate new immunotherapies’ efficacy faster than conventional methods such as radiographic imaging.

There’s still a long way to improve liquid biopsies; it has some limitations as sensitivity and access to these technologies, which can vary depending on the type of tumor, ctDNA can be modified by the burden and distribution of the disease, and also the economic costs for this study.

So far, it appears to be a great approach to continue monitoring ICI immunotherapies (response and efficacy), and it’s also a novel tool for testing new immunotherapies drug results.

Dr. Barco