High intensity focused ultrasound (HIFU) treatment of human pancreatic cancer

The authors performed a pilot study to evaluate both the ability of HIFU to ablate the pancreatic tumor xenografts PANG-1 and efficacy of combination of HIFU treatment with Gemcitabine, a novel antimetabolite chemotherapeutic agent. Gemcitabine hydrochloride (Gemzar(R)) was administered four times every 3 days. HIFU treatment was performed 24 hrs. After first Gemzar(R) injection. Sonablate-200/sup TM/ machine (Focus Surgery Inc.) was used for tumor HTFU ablation. Two spacing sizes between insonation points were used: 0.5 mm linear/spl times/0.8 mm transverse step and 1.0 mm linea/spl times/1.6 mm transverse step. In groups with step size 0.5/spl times/0.8 mm and 1.0/spl times/1.6 mm, 16 out of 16 and 14 out of 16 animals were cured respectively. Combination of Gemzar(R) and HIFU ablation with 1.0/spl times/1.6 mm step size resulted in 100% curative rate. Gemzar(R) alone resulted in 3.2 days of tumor quadrupling delay time. Also the authors simulated the situation when tumor cells are located in the near field of HIFU beam. Whereas treatment in the near field with HIFU alone resulted in 4.2 days of growth delay time, addition of Gemzar(R) to HIFU treatment increased tumor growth delay time up to 10.7 days. The authors' results demonstrate at least additive effect of combination of Gemzar(R) and HIFU ablation.