Impact of Extracorporeal Shock Wave Treatment on Dunning Prostate Tumors

Abstract

Recent studies have shown that directly exposing Dunning tumors to shock waves delayed or inhibited tumor growth. We examined the effects of extracorporeally generated shock waves on Dunning prostate tumor cells in vitro and in vivo using male Copenhagen rats. In two experiments, we subjected both tumor-bearing rats and precloned tumor cells in vitro to three different doses of shock waves (400, 800, and 1,600 shocks at 15 kV). Tumor growth in vivo was followed and measured weekly until tumor necrosis was evident. One-third of tumors subjected to 400 shocks at 15 kV showed significant delay in growth for 41 days after treatment; two-thirds of those subjected to 800 shocks at 15 kV showed delayed tumor growth for 70 to 80 days after treatment; and two-thirds of those subjected to 1,600 shocks at 15 kV showed inhibited growth for 40 to 70 days after treatment.

Half of the tumor cells treated in vitro were recultured, and half were injected subcutaneously into the legs of male Copenhagen rats. Cell counts taken on the recultured cells for six days following treatment were significantly lower in the treated group than in the untreated group. However, both groups produced tumors: the untreated cells at 42 days, and the treated cells at 67 days. Examination of treated cells by regular microscopy revealed no damage. Ultrastructural examination by transmission electron microscopy (TEM) revealed vacuolarization in the cytoplasm: first, alterations in mitochondrial membrane and total loss of cristae; second, breakage and swelling in the reticular endoplasmic system; third, swelling, increased membrane porosity, and chromatin damage in the nucleus.