Dr. Husain on Plasma-Based Testing in Lung Cancer

Hatim Husain, MD, assistant professor of Medicine, Moores Cancer Center, University of California, San Diego, discusses plasma-based testing in lung cancer.

There is a lot of interest in understanding the clinical applicability of plasma-based testing. Right now, plasma-based testing is FDA-approved when tissue is not obtainable, inadequate for testing, or unsafe. Husain advises that clinicians ensure that the tissue has been adequately addressed if a patient’s plasma test comes back negative. Plasma tests can be negative in relation to tumor mutational burden. Patients who have more contained and defined tumor burdens may have less detectability with plasma-based tests, says Husain. Plasma-based testing may also be limited in certain sanctuary sites such as the brain or bone.

A number of research projects are being done to understand the detectability of plasma and the dynamic changes of circulating-tumor DNA in plasma through time on therapy. Researchers believe that they will be able to understand the evolution of cancer and how through time, resistance can be identified early. Further work will address how one can intervene or better understand how to intervene and what metrics to look at in the face of identified resistance mechanisms.