Systemic immune response induced by radiofrequency ablation versus microwave ablation at varying powers in murine...

Thermal ablation for orthotopic tumors can activate the immune system, eliciting tumor-specific immune responses. With the recognition of the immune system's role in cancer outcomes and the demand for effective immunotherapies, there is a clinical need to optimize ablation techniques to enhance anti-tumor immunity. This study evaluates the effects of microwave ablation (MWA) and radiofrequency ablation (RFA) at varying powers and durations on systemic T cell profiles and cytokine levels.

Subcutaneous murine hepatocellular carcinoma (HCC) models were established. A total of 50 mice were randomly allocated into five groups, with 10 mice in each group: high-power MWA (10 W, 30 s), low-power MWA (5 W, 60 s), high-power RFA (10 W, 30 s), low-power RFA (5 W, 60 s), and untreated control group. Peripheral CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells, along with cytokines including interleukin (IL)-12, interferon-gamma (IFN-γ), IL-4, and IL-10, were determined 14 and 28 days after the ablation.

High-power (10 W) ablation boosted adaptive immunity on day 14 post-procedure, manifested as significantly elevated CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells and a Th1-skewed immune response (increased IL-12 level and decreased IL-4 and IL-10 levels). By day 28, the CD3⁺CD4⁺ T cells had risen further, although the CD3⁺CD8⁺ T cells had declined; additionally, the IL-10 level remained low, the IL-12 level normalized, and IFN-γ was stable.

High-power MWA and RFA can notably activate systemic immunity and enhance Th1 response. These findings underscore the potential of optimizing ablation parameters (such as higher power and shorter duration) to amplify anti-tumor immunity, bridging local tumor control with systemic immune activation.