Poster Sessions

CANCER-7

Hilary Hancock

H. Hancock, M. Dreher, N. Crawford, B. Wood, K. Hunter, V. Frenkel

Examination of Effects of Pulsed High-intensity Focused Ultrasound Exposures on Metastasis in a Breast Cancer Cell Line in a Murine Model

High intensity focused ultrasound (HIFU) can be used in continuous mode for thermal ablation (>60ºC), and pulsed mode for hyperthermia (37–45ºC), and for inducing non thermal effects (e.g. acoustic cavitation and radiation forces). The latter may enhance tissue permeability for improved delivery of therapeutics, by opening up gaps between cells in the vasculature and parenchyma. Concerns exist however that such effects could facilitate dissemination of tumor cells. This study evaluated the influence of pulsed-HIFU exposures on metastatic burden in a murine flank tumor model. A preliminary study first validated the model and determined optimal timing for treatment of primary tumors and growth of lung metastases. Effects of pulsed-HIFU on metastatic burden were then evaluated using quantitative image processing of whole-lung histological sections. Compared to untreated controls (2/15), a greater number of mice treated with pulsed-HIFU were found to have extensive lungs metastases (7/15), where individual lesions grew together and could not accurately be counted. Area fraction of metastases (per area of lungs) was 30% greater in mice treated with pulsed-HIFU; however, differences were not statistically significant. This study details the development of an animal model for investigating the influence of interventional techniques, such as pulsed HIFU, on metastatic burden.