Early variations of circulating IL-6 and IL-10 during thoracic irradiation are predictive for incidence of radiation pneumonitis in patients with non small cell lung cancer: Results from a prospective study

Abstract

7079 Background: Radiation pneumonitis (RP) is the toxicity of 3D-CRT in irradiated patients. The goals of this study were to evaluate the predictive value of circulating cytokines levels before, during and after 3D-CRT for the risk of radiation pneumonitis (RP) in patients (pts) with NSCLC. Methods: 96 pts receiving 3D-CRT for stage IA-IIIB were evaluated. Serum IL-6, IL-10, TNFα and TGFβ1 levels were measured using specific ELISAs before, every 2 weeks (w.) and 2 months (m.) after 3D-CRT. RP was diagnosed 2 m. after 3D-CRT using Lent-Soma score. All were reviewed by independent panel. A repeated measures analysis of variance was used to analyze the variations of cytokines levels during and after 3D-RCT. In addition, AUC was calculated during RT for each cytokine using the trapezoid rule. Non parametric Mann-Whitney's exact test was used to test the impact of cytokines levels at baseline and during 3D-CRT on RP. Results: 6 pts could not be evaluated for RP 2 m. after RT. Of the 90 remaining pts, 40 had a RP (grade ≥ 1) including 7 pts with severe RP (grade ≥ 2). At baseline, increased IL-6 (>20 pg/mL), IL-10 (>50 pg/mL) and TNFα (>20 pg/mL) were observed in 4, 16 and 32 respectively. Median TGFβ1 was 36 ng/mL (r: 0–76 ng/mL). Initial IL-6, IL-10, TNFα and TGFβ1 levels were not correlated to clinical characteristics or incidence of RP. During RT, mean serum TGFβ1 decreased in the whole group (mean 38 vs 32 ng/mL, p<0.001), while values remained stable for others cytokines. IL-6 and IL-10 levels showed opposite evolution: during RT, the AUC of IL-6 p was found to be significantly > in pts with RP compared to pts who did not. (1570 vs 246, p=0.03). Difference reached significance at 2 w. of treatment (Tt.) with a peak of IL-6 in RP pts (53.2 vs 3.4 pg/mL, p=0.025). In contrast, the chronological changes in serial serum IL-10 levels showed a peak at 2 w. of Tt. in pts who did not developed RP compared to pts with RP (82.3 vs 29.0 pg/mL). TNFα and TGFβ1 were not correlated with the risk of RP. Conclusions: Variations of IL-6 and IL-10 levels during 3D-CRT are strongly predictive for development of RP after RT. No significant financial relationships to disclose.