SIR 2024
Interventional Oncology
Nathan Loudon, MD
Interventional Radiology Resident
University of Michigan
Financial relationships: Full list of relationships is listed on the CME information page.
Valerie Khaykin, BS
Research Coordinator
University of Michigan
Disclosure information not submitted.
Maggie Zhang, MD, PhD
Assistant Professor
University of Michigan
Disclosure information not submitted.
Neehar Parikh, MD, MS
Assistant Professor
University of Michigan
Disclosure information not submitted.
Cliff Cho
Disclosure information not submitted.
Mishal Mendiratta-Lala, MD
Professor of Radiology
University of Michigan
Financial relationships: Full list of relationships is listed on the CME information page.
Histotripsy is a non-invasive ablation modality that utilizes high-pressure ultrasound pulses to disrupt cellular architecture and induce tissue necrosis. Research suggests that histotripsy might trigger an abscopal response, a phenomenon where local tumor ablation induces systemic antitumor effects. This response is attributed to the release of tumor antigens and damage-associated molecular patterns which stimulate the immune system and enhance the overall antitumor immune response. Compared to other ablation modalities, it is theorized that histotripsy’s unique mechanical, non-thermal mechanism may better preserve tumor antigens previously unrecognized by the immune system. This may partially explain the promising preclinical and early clinical evidence for histotripsy-induced abscopal response.
Clinical Findings/Procedure Details:
Preclinical investigations have demonstrated an abscopal effect following histotripsy in murine liver tumor and melanoma models. A study evaluating histotripsy of hepatocellular carcinoma in rats was the first to suggest a histotripsy-induced abscopal effect. A 2020 study comparing histotripsy to radiotherapy and radiofrequency ablation showed marked increase in CD8+ T-cell infiltration at histotripsy treated tumors in conjunction with decreased size of distant metastases in the histotripsy treated group. Additionally, a recent study showed the involution of tumors which were only partially treated by histotripsy, further highlighting its immunogenic properties. Finally, in the first human clinical trial (the THERESA trial) involution of non-treated tumors was seen in a patient with metastatic colorectal carcinoma with a corresponding decrease in CEA levels.
Conclusion and/or Teaching Points:
There is promising early evidence for histotripsy-induced abscopal response in both pre-clinical trials and the initial clinical trial. The ability to generate immune response in tumors distant from the ablated lesion may lead to new cancer treatment strategies. Further investigation into the optimization of histotripsy parameters and a deeper understanding of the immunologic mechanisms involved will be necessary to determine the clinical utility of histotripsy-induced abscopal response.