The First International Experience with Histotripsy: A Safety Analysis of 230 Cases.

Abstract

Introduction: Histotripsy is a novel, non-invasive, non-ionizing, non-thermal approach using focused ultrasound waves to treat liver tumors. The technology received FDA De Novo grant in late 2023. We aim to provide the first reporting of post-trial, real-world clinical safety data.

Methods: Safety outcomes within 30 days of histotripsy were collected since FDA clearance (12/22/2023 - 7/25/2024). All centers who have performed histotripsy were invited to participate. Complications requiring treatment were graded using Clavien-Dindo and Comprehensive Complications Index (CCI).

Results: In total, 295 patients received histotripsy to 510 tumors at 18 centers. Treated liver tumor types included colorectal metastases (n=140), neuroendocrine (n=46), hepatocellular carcinoma (n=31), pancreas (n=30), and breast metastases (n=26). The most common number of tumors treated per procedure were 1 (n=170), 2 (n=69), and 3 (n=37). Tumors were treated in all 8 liver segments. Safety data was available for 230 patients from 9 centers. A total of 12 out of 230 patients experienced complications of any grade (5.2%). Most (n=9, 75%) were minor (< Clavien-Dindo Grade II). Median and mean CCI were 0 (IQR 0-0) and 0 points (95%CI 0-0.75). All three major complications (>Clavien-Dindo grade II, 1.3%) were death from disease progression. All three of these patients had undergone histotripsy with palliative intent for known advanced intra- and extrahepatic disease.

Conclusions: This is the first report on the real-world therapeutic use of histotripsy for liver tumors. Histotripsy was well tolerated with few overall complications and rare serious complications indicating a safety profile which compares favorably with other liver-directed and surgical therapies for the treatment of liver tumors. Long-term follow-up data including oncologic outcomes are being collected.