Immunomodulation after radiofrequency ablation of locally advanced pancreatic cancer by monitoring the immune response in 10 patients

Abstract

Objective/background: RFA of pancreatic cancer has been demonstrated to be feasible and safe with a positive impact on survival. The aim was to investigate whether an immune reaction is activated after locally advanced pancreatic cancer (LAPC) ablation.

Methods: Peripheral Blood samples were obtained preoperatively and on post-operative days 3-30. Evaluated parameters were: cells [CD4⁺, CD8⁺ and activated subsets, T-Reg, Monocytes, myeloid and plasmocytoid Dendritic cells (mDC and pDC)] and cytokines [Interleukin (IL)-6, Stromal-cells derived factor (SDF)-1, IL-1β, Tumour-Necrosis Factor (TNF)-α, Interferon (IFN)-γ, Vascular Endothelial Growth Factor (VEGF), chemokine (C-C motif) ligand 5 (CCL-5), Transforming-Growth Factor (TGF)-β].

Results: Ten patients were enrolled. CD4⁺, CD8⁺ and TEM increased from day 3 suggesting the activation of the adaptive response. Immunosuppressive T-Reg cells were stable despite the possibility that laparotomy and heating might favour their expansion. Myeloid DCs, that present tumour-associated antigens, increased at day 30. RFA dramatically increased circulating IL-6 at day 3 but this decreased to baseline by day 30, consistent with the supposed anti-tumour effect. RFA did not significantly modulate essential chemokines, such as CCL-5 and SDF1, VEGF, TGF-β and TNF-α, that favour tumour-growth by sustaining cancer angiogenesis and fuelling tumour-associated inflammation.

Conclusions: This study provides the first evidence of RFA-based immunomodulation in LAPC. We observed a general activation of adaptive response along with a decrease of immunosuppression. Furthermore, most cells showed prolonged activation some weeks after the procedure, suggesting true immunomodulation rather than a normal inflammatory response.

Keywords: IL-6; Immune response; Pancreatic cancer; Radiofrequency ablation; T regulator lymphocytes.