The effects of
radiotherapy on systemic immunity remain to be fully characterized in a disease-specific manner. The aim of the study was to examine potential
biomarkers of systemic
immunomodulation when using
radiotherapy for thoracic
malignancies. Serial blood samples were collected from 56 patients with thoracic
malignancies prior (RTbaseline), during (RTduring) and at the end of
radiotherapy (RTend), as well as at the first (FU1) and second follow-up (FU2). The changes in serum levels of
IL-10, IFN-γ, IL-12p70,
IL-13, IL-1β,
IL-4,
IL-6,
IL-8, TNF-α, bFGF, sFlt-1, PlGF,
VEGF,
VEGF-C,
VEGF-D and HGF were measured by multiplexed array and tested for associations with clinical outcomes. We observed an increase in the levels of
IL-10, IFN-γ, PlGF and
VEGF-D and a decrease in those of
IL-8,
VEGF,
VEGF-C and sFlt-1 during and at the end of
radiotherapy. Furthermore, baseline concentration of TNF-α significantly correlated with OS.
IL-6 level at RTend and FU1,2 correlated with OS (RTend: p = 0.039, HR: 1.041, 95% CI: 1.002-1.082, FU1: p = 0.001, HR: 1.139, 95% CI: 1.056-1.228, FU2: p = 0.017, HR: 1.101 95% CI: 1.018-1.192), while
IL-8 level correlated with OS at RTduring and RTend (RTduring: p = 0.017, HR: 1.014, 95% CI: 1.002-1.026, RTend: p = 0.004, HR: 1.007, 95% CI: 1.061-1.686). In conclusion, serum levels of TNF-α,
IL-6 and
IL-8 are potential
biomarkers of response to
radiotherapy. Given the recent implementation of
immunotherapy in lung and
esophageal cancer, these putative blood
biomarkers should be further validated and evaluated in the combination or sequential
therapy setting.