S5874 Histotripsy: A New Era in Liver Cancer Treatment—Image-Guided, Non-Invasive Tumor Ablation Without Chemotherapy, Radiation, or Incision

Introduction: Histotripsy is a novel, non-invasive focused ultrasound technique that uses high-amplitude, microsecond pulses to generate a “bubble cloud,” mechanically destroying and liquefying targeted tissue without heat or ionizing radiation. Unlike thermal ablation, histotripsy offers submillimeter precision with minimal collateral damage and is particularly advantageous for treating tumors near critical structures like blood vessels and bile ducts. Its non-thermal mechanism avoids the “heat-sink effect,” enhancing efficacy in vascular-rich organs such as the liver. This makes histotripsy a promising option for patients who are poor surgical candidates or require tumor downstaging. We present a case where histotripsy was used to treat a metastatic liver lesion, resulting in radiographic improvement and symptom resolution. Case Description/Methods: An 85-year-old woman with a history of renal cell carcinoma (status post nephrectomy) and high-grade serous ovarian carcinoma with peritoneal carcinomatosis (diagnosed in 2017, previously treated with chemotherapy and in remission) presented with recurrence involving the liver. Due to her age, comorbidities, and lesion location, she was deemed ineligible for surgical resection. On January 13, 2025, she underwent histotripsy targeting a hepatic metastasis measuring 3.5 × 2.5 cm in segment VI. Post-procedure, she experienced mild nausea, dizziness, and headache for 1–2 days, which resolved over the following weeks. A follow-up magnetic resonance imaging (MRI) on March 1, 2025, showed a peripherally enhancing treatment cavity up to 29 mm with a central non-enhancing component, appearing nonviable. Continued surveillance was recommended. A repeat MRI on May 12, 2025, demonstrated a decrease in treatment zone size to 1.4 × 0.9 cm, with resolved rim enhancement, consistent with effective ablation. Discussion: This case highlights the potential of histotripsy as a safe, effective, and non-invasive locoregional therapy for both primary and metastatic liver tumors. Its ability to achieve precise tumor ablation without thermal or radiation-related injury makes it particularly valuable for patients who are poor surgical candidates or require tumor downstaging. As clinical experience grows, histotripsy may become an important tool in the multidisciplinary management of hepatic malignancies, offering a transformative alternative in liver cancer care.