Extravesical cryosurgical approach for VX2 bladder tumor in rabbits

This study characterized the VX2 bladder cancer model in rabbits and tested the feasibility of treating bladder cancer by extravesical cryosurgery. Af ter the growth characteristics of the VX2 bladder tumor model were determin ed, the VX2 tumor was inoculated into rabbits at the dome of the bladder. O ne week later, three freeze/thaw cycles were followed by immediate surgical repair. The control group underwent a sham operation without freezing. Whe n the VX2 tumor is injected into the bladder wall, invasion and central nec rosis occurred within 1 week, lymphatic metastases by 2 weeks, and lung met astases by 3 weeks after inoculation. By 4 weeks, all control rabbits had l arge VX2 tumors in their bladders and advanced lung metastases. Nine of the ten rabbits in the cryosurgical group had mild to moderate degrees of lung metastases, and six of them had relatively small local recurrences. One ra bbit had no tumor in the bladder and only microscopic lung metastasis. The extravesical approach to cryosurgery employing bladder inversion is well to lerated. Cryosurgery exhibits modest efficacy in treating local tumors and delaying lung metastasis in this aggressive tumor model.