Cytokines in bronchoalveolar lavage fluid and serum of lung cancer patients during radiotherapy — Association of interleukin-8 and VEGF with survival

Radiotherapy (RT) produces oxidative stress and local inflammation. This study aimed at clarifying the role of different cytokines (VEGF, TNFα, IL-1β, IL-6, IL-8, IL-12 and IL-18) in bronchoalveolar lavage (BAL) fluid and in the serum of lung cancer patients at baseline and during RT. Bronchoscopy and BAL were performed on 36 lung cancer patients and 36 controls for diagnosis; patients receiving RT had a second bronchoscopy during RT. Serum samples were obtained during RT and three months after RT. In this study lung cancer patients had higher levels of serum and BAL fluid IL-6 and serum IL-8 compared to controls (p < 0.001, p = 0.039 and p = 0.030, respectively). RT caused a significant increase of BAL fluid IL-6 (p = 0.037). There were no significant associations between baseline cytokine levels and adverse events or response to treatment. Higher baseline serum and BAL fluid IL-8 and serum VEGF levels (p = 0.036, p = 0.027 and p = 0.014, respectively) were associated with shorter survival. This study shows that lung cancer is associated with upregulation of IL-6 and IL-8. The increase of BAL fluid IL-6 during RT might be attributed to enhanced RT-related oxidative stress or increased cell death. Serum and BAL fluid IL-8 and serum VEGF might have a prognostic role in survival of lung cancer.