A novel liquid biopsy test may help determine which patients with non-small cell lung cancer (NSCLC) would most benefit from targeted radiation. The findings will be presented at the American Society for Radiation Oncology 2023 Annual Meeting and published in npj Precision Oncology.
Liquid biopsy tests are capable of detecting elements of solid tumor cancers in blood, urine, or cerebrospinal fluid and are often utilized to identify circulating tumor DNA (ctDNA), circulating tumor cells, circulating RNA, and other biomarkers that signal the presence of cancer.
In this real-world, multi-institutional analysis, the researchers assessed data on 309 patients (average age, 64.7 years) with oligometastatic NSCLC who received radiation therapy following liquid biopsy from 2016 to 2022. Oligometastatic disease was defined as metastatic disease in at least 1, and up to 5, organ systems.
The analysis showed that patients with detectable ctDNA prior to radiation therapy had worse overall survival than those with no detectable pretreatment ctDNA. Progression-free survival was also worse for those whose blood showed traces of ctDNA prior to radiation therapy, the investigators noted. The results indicated that patients with no or low levels of detectable ctDNA were most likely to benefit from targeted radiation therapy, whereas those with higher levels of ctDNA were more likely to require systemic chemotherapy or immunotherapy.
“Our findings suggest the level of circulating tumor DNA, rather than the number of tumors themselves, is a more precise measure of disease burden,” said senior study author Aadel Chaudhuri, MD, PhD, an assistant professor of radiation oncology at the Siteman Cancer Center of Washington University School of Medicine in St. Louis, via a press release.
Dr. Chaudhuri added that when “you have a detectable ctDNA level, you have a higher burden of disease. Our findings indicate that we can use this biomarker to support patient-centered treatment decisions in the oligometastatic cancer setting.”