Microwave ablation enhances the systemic immune response in patients with lung cancer

Microwave ablation (MWA) is a key alternative therapy to conventional surgery for the treatment of lung cancer. In addition to eliminating local tumors, MWA may promote antitumor immunological responses, such as abscopal effects in distant lesions. However, the intensity of MWA is limited and the underlying mechanisms are not well-defined. The present study assessed the impact of MWA on immune cell subsets and cytokines in patients with lung cancer. A total of 45 patients with lung cancer who underwent percutaneous lung tumor MWA were enrolled. Peripheral blood samples were collected before and 24 h after MWA and changes in immune cell subsets [lymphocytes, CD3⁺, CD4⁺ and CD8⁺ T cells, B cells and natural killer (NK) cells] and serum cytokine levels (IL-1β, IL-2, IL-4-6, IL-8, IL-10, IL-12p70, IL-17A and F, IL-22, TNF-α, TNF-β and IFN-γ) were assessed by flow cytometry and ELISA. The number of total lymphocytes, CD4⁺ T and NK cells in the peripheral blood significantly decreased 24 h after MWA, while number of CD8+ T cells remained stable, leading to a higher proportion of CD8⁺ T cells. In addition, the serum levels of IL-2, IL-1β, IL-6, IL-12p70, IL-22, TNF-α and IFN-γ were significantly increased 24 h after MWA, indicating a T helper 1 type immune response. The immune response in patients with advanced stage disease was comparable with patients in the early stage group; however, the number of total lymphocytes and CD3⁺ T cells significantly decreased and the ratio of CD4/CD8 and IL-2 levels significantly increased. The early immune response after MWA may contribute to systemic antitumor immunity in patients with both early and advanced disease. Thus, MWA may exhibit potential as a local therapy and trigger abscopal effects in distant lesions in patients with lung cancer.