Increased Tissue Penetration of Doxorubicin in Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) after High-Intensity Ultrasound (HIUS).

Background: High-intensity ultrasound (HIUS) has been studied for the past two decades as a new therapeutic option for solid tumor direct treatment and a method for better chemotherapy delivery and perfusion. This treatment approach has not been tested to our knowledge in peritoneal metastatic therapy, where limited tissue penetration of intraperitoneal chemotherapy has been a main problem. Both liquid instillations and pressurized aerosols are affected by this limitation. This study was performed to evaluate whether HIUS improves chemotherapy penetration rates.

Methods: High-intensity ultrasound (HIUS) was applied for 0, 5, 30, 60, 120, and 300 seconds on the peritoneal tissue samples from fresh postmortem swine. Samples were then treated with doxorubicin via pressurized intraperitoneal aerosol chemotherapy (PIPAC) under 12 mmHg and 37°C temperature. Tissue penetration of doxorubicin was measured using fluorescence microscopy on frozen thin sections.

Results: Macroscopic structural changes, identified by swelling of the superficial layer of the peritoneal surface, were observed after 120 seconds of HIUS. Maximum doxorubicin penetration was significantly higher in peritoneum treated with HIUS for 300 seconds, with a depth of 962.88 ± 161.4 μm (p < 0.05). Samples without HIUS had a penetration depth of 252.25 ± 60.41. Tissue penetration was significantly increased with longer HIUS duration, with up to 3.8-fold increased penetration after 300 sec of HIUS treatment.

Conclusion: Our data indicate that HIUS may be used as a method to prepare the peritoneal tissue for intraperitoneal chemotherapy. Higher tissue penetration rates can be achieved without increasing chemotherapy concentrations and preventing structural damage to tissue using short time intervals. More studies need to be performed to analyze the effect of HIUS in combination with intraperitoneal chemotherapy.