Assessment of circulating tumor DNA and cytokine levels in plasma of patients with non-small cell lung cancer after local irradiation of the tumor site

Liquid biopsy is a promising method for non-invasive diagnosis in oncological patients. However, due to the extremely low concentration of free circulating tumor DNA (ctDNA), especially minor clones, the detection requires the use of a comprehensive set of high-tech methods. The induction of the release of ctDNA into the bloodstream through tumor irradiation may improve the diagnostic sensitivity of ctDNA-tests in patients with non-small cell lung cancer (NSCLC). At the same time, systemic inflammation and the levels of pro-inflammatory cytokines within the body can exert influence on the concentration of free circulating DNA at certain time points after irradiation.

According to our data, local irradiation of tumor sites leads to an increase in ctDNA levels, reaching a maximum after 48 hours. The presence of statistically significant differences in the frequencies of maximum and minimum concentrations of cytokines IL-15, IL-4, IL-1ra, and VEGF was observed in serial blood plasma samples from patients with NSCLC, depending on the level of ctDNA.

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