In vivo effects of cavitation alone or in combination with chemotherapy in a peritoneal carcinomatosis in the rat.

Cavitation (volume oscillations and collapse of gas bubbles), as generated by a co-administration of shockwaves (SW) and microbubbles (SWB), induces cytotoxicity in vitro. Moreover, cavitation potentiates the effects of Fluorouracil (FUra) on colon cancer cells. We aimed at reproducing such effects in vivo. A peritoneal carcinomatosis was induced in BDIX rats by intraperitoneal (IP) injection of DHDK12PROb cells. Cavitation was produced by various SW regimens (250 to 750SW) combined with bubbles (air/gelatin emulsion) infused through an IP catheter. In two consecutive experiments, microtumours (day 3 after cell injection) were submitted to various combinations of cavitation and/or Fluorouracil (FUra) and Cisplatinum (CDDP) at either high or low doses. After 30 days, 100% of control animals were dead or presented carcinomatosis with ascites, vs 60% after FUra 5 mg kg dy, day 4 through 8, and 0% after 250 SWB, day 4 and 6 + FUra 5 mg kg dy, day 4 through 8 (P < 0.001); similar differences were found with CDDP. Survival after low dose FUra + SWB was comparable to high dose FUra (25 mg kg dy day through 8) and was improved as compared to low-dose FUra alone. Only a high dose FUra + SWB schedule induced 40% long term (> 150 days) disease-free survival, but also a higher undesirable toxicity (40% toxic deaths within 1 month). It is concluded that cavitation is cytotoxic in vivo and that it potentiates the effects of FUra and CDDP in this animal model.