Results of two clinical studies have added to evidence that blood-based liquid biopsies can accurately track lung cancer treatment responses by measuring circulating tumor DNA (ctDNA) during immunotherapy and related treatments.

“There is an unmet clinical need for real-time, noninvasive detection of tumor response to targeted and immune checkpoint blockade treatments,” says Victor Velculescu, MD, PhD, co-director of cancer biology at the Johns Hopkins Kimmel Cancer Center. “Our studies suggest that tests using blood samples will change the way cancer patients will be treated by helping to evaluate therapeutic responses more quickly and accurately, and avoid unneeded toxicity or ineffective treatments.”

The new studies, described in the December issues of the journal Cancer Research, showed that tracking responses to treatment by measuring ctDNA was a more accurate way of assessing tumor growth or shrinkage than traditional imaging techniques.

In a study of 28 adult patients with advanced non-small cell lung cancer (NSCLC), blood samples were taken prior to anti-EGFR (epidermal growth factor receptor) or anti-HER2 (human epidermal growth receptor 2) treatments—which target cancer growth—and at intervals thereafter.