Objective: Osteosarcoma (OS) is a devastating primary bone tumor in dogs and humans with limited nonsurgical treatment options. As the first completely non-invasive and non-thermal ablation technique, histotripsy has the potential to significantly improve the standard of care for patients with primary bone tumors. Introduction: Standard of care treatment for primary appendicular OS involves surgical resection via either limb amputation or limb-salvage surgery for suitable candidates. Biological similarities between canine and human OS make the dog an informative comparative oncology research model to advance treatment options for primary OS. Evaluating histotripsy for ablating spontaneous canine primary OS will build a foundation upon which histotripsy can be translated clinically into a standard of care therapy for canine and human OS. Methods: Five dogs with suspected spontaneous OS were treated with a 500 kHz histotripsy system guided by real-time ultrasound image guidance. Spherical ablation volumes within each tumor (1.25-3 cm in diameter) were treated with single cycle histotripsy pulses applied at a pulse repetition frequency of 500 Hz and a dose of 500 pulses/point. Results: Tumor ablation was successfully identified grossly and histologically within the targeted treatment regions of all subjects. Histotripsy treatments were well-tolerated amongst all patients with no significant clinical adverse effects. Conclusion & Significance: Histotripsy

Objective To determine the influence of administering allogeneic blood products (ABP) on the progression of hemangiosarcoma in dogs. Study design Multi‐institutional, retrospective study. Sample population One hundred four dogs with hemangiosarcoma that survived until postoperative discharge from the hospital. Methods Medical records of dogs that had been operated on for hemoangiosarcoma were reviewed for signalment, presence of a hemoabdomen, presence of metastatic disease, and whether the dog had received chemotherapy or Yunnan Baiyao. Data that were collected were compared between dogs that received perioperative ABP and those that did not. Disease‐free interval was compared between groups. The Kaplan‐Meier method was used to obtain univariate descriptive statistics for time to clinical decline. A multivariable Cox regression model was used to analyze association or effect of potential predictor variables. Results The median disease‐free interval (DFI) was shorter in the 67 dogs that received a blood transfusion (76 days; range, 1‐836) than in the 37 dogs that did not receive a blood transfusion (120 days; range, 38‐916). According to the multivariable Cox regression model, administration of blood products (P = .04) and the presence of gross metastatic disease at the time of surgery (P < .01) shortened the DFI, whereas administration of Yunnan Baiyao (P = .01) prolonged the DFI. Conclusion Allogeneic blood product administration was associated with a shorter disease‐free interval in this population. However, we could not demonstrate the association between blood products and shorter DFI because of confounding factors. Clinical significance Dogs that receive ABP at the time of surgical therapy for hemangiosarcoma may have accelerated disease progression compared with dogs that do not receive ABP.

A combination of IOCS and LRF processing may provide an alternative to allogeneic blood transfusion in dogs with hemoabdomen due to HSA.

Osteosarcoma (OS) is a malignant bone tumor treated by limb amputation or limb salvage surgeries and chemotherapy. Histotripsy is a non-thermal, non-invasive focused ultrasound therapy using controlled acoustic cavitation to mechanically disintegrate tissue. Recent ex vivo and in vivo pilot studies have demonstrated the ability of histotripsy for ablating OS but were limited in scope. This study expands on these initial findings to more fully characterize the effects of histotripsy for bone tumors, particularly in tumors with different compositions. A prototype 500 kHz histotripsy system was used to treat ten dogs with suspected OS at an intermediate treatment dose of 1000 pulses per location. One day after histotripsy, treated tumors were resected via limb amputation, and radiologic and histopathologic analyses were conducted to determine the effects of histotripsy for each patient. The results of this study demonstrated that histotripsy ablation is safe and feasible in canine patients with spontaneous OS, while offering new insights into the characteristics of the achieved ablation zone. More extensive tissue destruction was observed after histotripsy compared to that in previous reports, and radiographic changes in tumor size and contrast uptake following histotripsy were reported for the first time. Overall, this study significantly expands our understanding of histotripsy bone tumor ablation and informs future studies for this application.