Improvement of immune response after radiofrequency ablation in colorectal cancer.

102Background: Radiofrequency ablation (RFA) efficiency of liver tumors is compromised by high rates of relapse. Death of cancer cells by hyperthermia induced tumor antigen releasing, expression of danger signals that activate a specific T-cell response. This effect is ineffective to avoid recurrence. We propose to combine RFA with priming of a strong immune antitumor response as curative treatment of an aggressive colorectal cancer (CRC) in immunocompetent mouse. Methods: RFA was used to treat a CT26-luc tumor as primary lesion. In two distinct clinical situations, macroscopic or microscopic distant tumors were established as secondary lesions. The immune response was modulated by the injection, in the treated area, of a thermo-reversible hydrogel loaded by GM-CSF and BCG, targeting recruitment and maturation of dendritic cells. In mice with far large lesions, this strategy was combined with PD1checkpoint inhibition. The efficiency was assessed on survival, evolution of distant lesions, characterization ...