(16) Treating Hepatic Tumors with Histotripsy: Insights from the THERESA Trial and Literature Review

Priyali Saxena, Medical Student – Medical Student, University of Illinois College of Medicine; Faisal Al-Qawasmi, Medical Student – Medical Student, University of Illinois College of Medicine

Purpose: Histotripsy, an emerging advanced technology, offers a non-invasive approach to tumor removal without heat or ionizing radiation. By utilizing ultrasound, it creates small bubbles that oscillate and collapse through acoustic cavitation, resulting in cell fragmentation. This technique effectively liquefies bulk tissue, including tumors, into an acellular homogenate. The body naturally absorbs the debris within 1-2 months, leaving only minor scars. Post-treatment evaluation can be accomplished using MRI. Histotripsy shows promising potential as a novel treatment for primary and secondary hepatic tumors. This abstract aims to review the application and potential advantages of histotripsy in this context.

Material and Methods: A systematic literature review was performed using the PubMed database with the search term "hepatic histotripsy" to assess the safety and outcomes of histotripsy as a treatment for hepatic tumors.

Results: The THERESA trial, using the HistoSonics System, investigated histotripsy as a treatment for primary and secondary hepatic malignancies. The trial included eight patients with tumors ranging from 0.5-2.1 cm, including hepatocellular carcinoma (HCC) and metastatic liver cancer. The primary endpoint of achieving tissue destruction within the planned volume was successfully met for all procedures, confirmed by MRI evaluation. No significant adverse events occurred, except for a mistargeted tumor. Tumors exhibited regression and decline in tumor markers, with shrinkage of non-target tumors observed. The HistoSonics System was also successful in treating HCC and liver metastases at an academic institution, with confirmed ablation and no adverse events reported.

Conclusions: Histotripsy is an innovative treatment for hepatic tumors, offering advantages such as real-time ultrasound feedback to optimize energy deposition and minimize unintended effects. It avoids thermal energy deposition, reducing harm to surrounding structures. The THERESA trial demonstrated histotripsy's potential for inducing an abscopal effect in humans, with implications for future cancer therapies. Prospective clinical trials are currently evaluating the efficacy of the HistoSonics System for liver lesions.