FUS Canine Cancer Project

Application of thermal or mechanical ablation using focused ultrasound can modify the tumor microenvironment. In this project, we compared the therapeutic and immunological effectiveness of thermal and boiling histotripsy-based focused ultrasound (FUS) ablations against canine cancers. We found that FUS thermal ablations were relatively more effective in attaining tumor remissions compared to histotripsy against a variety of tumor types in the cancer patients. Although promising, however, even with conformal therapy, normal tissue toxicities were noted with thermal ablations especially when the targeted tumors were located close to regions with high acoustic absorption (e.g., bone). In contrast, histotripsy exposures were safe for the tumor adjoining healthy tissues, and the patients tolerated the treatments without any alterations in the vital signs. The immune activations from both thermal ablation and histotripsy depended on the tumor types, with some patients showing enhanced proliferation of anti-tumor immune cells in blood and biopsy samples post-treatment than the others. In summary, our findings suggest that relative to mechanical histotripsy, thermal ablation is more effective in attaining tumor remissions in canine patients. Immunological responses with both thermal and mechanical ablations are dependent on the tumor types. A more detailed study should be performed to verify such effects in a large cohort of patients with a single tumor type and variable mechanical or thermal ablation rates.