[The anticancer effects of high energy shock waves on rat bladder cancer induced by BBN]

The in vivo anticancer effects of high energy shock waves (HESW), on bladder cancer induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), were studied in the rat using the Siemens lithotriptor (Lithostar). There was no significant difference in the anticancer effects in delaying tumor growth, measured as the whole bladder weight including the weight of the cancer, between the groups with and without exposure to HESW. However, light microscopic examination revealed extensive submucosal bleeding and exfoliation of mucosa, and electron microscopic examination revealed degeneration of pleomorphic microvilli, swelling of mitochondria, and destruction of mitochondrial cristae in the cancer cells in bladders exposed to HESW. Flow cytometric determination of DNA content in the cancer cells exposed to HESW indicated a selective diminution of cells in the G2 and M phases and an increase of cells in the G0 and G1 phases of the cell cycle. While the mechanism of HESW-induced anticancer effect could not be determined on the basis of this study, these changes in the morphology and the cell cycle of cancer cells induced by HESW exposure suggest some kind of biological effects following exposure to HESW. It is expected that HESW be an effective method for the treatment of human cancer in combination with chemotherapy and radiation.