Chairman, Dept of Urology RAMBAM HealthCare Campus
Introduction: Non-muscle-invasive bladder cancer (NMIBC) accounts for 75% of new bladder cancers. Current destructive treatment options have not significantly changed in several decades. Surface spray cryotherapy (cryo), is being used by dermatologists and gynecologists extensively, and it has been shown to be highly effective in destroying surface lesions. We developed a surface cryotherapy device to treat NMIBC and conducted a series of animal studies in order to demonstrate device’s preliminary safety and efficacy, in a bladder environment.
Methods: Porcine model was used and areas of approximately one square centimeter were ablated (2-4 areas per bladder) at increasing times of exposure (5-15 seconds). We followed the animals for 3-5 days and then bladders were harvested and examined grossly and histologically.
Results: In 12 pigs, 38 areas in respective bladders were ablated. The procedure was performed with our novel device via standard rigid cystoscope after inflating the bladder with CO2. No adverse events were observed during the procedure and for 3-5 days of follow-up. Thereafter, harvesting was performed. Grossly, no bladder perforations were observed. Histology (H&E) showed ablation depth of 1-8 mm according to aggressiveness of the cryo protocol. Necrosis and/or fibrosis were present at the ablation area, with no perforation.
Conclusions: Surface cryotherapy is a potential paradigm shift in the treatment of superficial bladder cancer. Tissue response to the cryo spray can be seen in real-time, allowing us to assess destruction of the tissue. Visualization is excellent and is not affected by the cryo spray at all procedure stages. Histologic results demonstrated efficacy of tissue destruction and safety since there was no bladder perforation or bleeding. Depth of destruction was directly correlated and controlled by the time of exposure to the cryo spray. These encouraging preliminary results may allow us to proceed to first-in-human clinical trials. These were approved by regulatory authorities and are underway.