Key Points
- Histotripsy was cleared by the US FDA for the treatment of primary and metastatic liver tumors almost three years ago.
- Researchers sought to gather an early national snapshot of its use for this indication.
It is approaching three years since the US Food and Drug Administration (FDA) cleared the HistoSonics Edison histotripsy system for the treatment of primary and metastatic liver tumors. With interest in how the adoption and use of the technology has proceeded since then, a research team at the University of Virginia led by Allan Tsung, MD, professor and chair of the Department of Surgery, sought to gather an early national snapshot of its use for this indication.
Early Outcomes of Histotripsy for Liver Tumors in US Clinical Practice
Dr. Tsung and his team conducted an analysis of electronic health records to evaluate liver histotripsy practice patterns and short-term outcomes in the United States.
Methods
Using a retrospective group of deidentified patient data from a large electronic health record, the team searched for adult patients who had undergone the histotripsy procedure billing code (0686T). The search produced information on 972 patients, including their demographic, geographic, and diagnostic information, along with laboratory results before and after undergoing liver histotripsy.
Patient and Diagnostic Breakdown
The patients:
- Were a median age of 67.0 (56.0-74.3) years and fairly equally divided by gender (51.4% male, 48.6% female)
- Were mostly (88.2%) treated in urban centers, in a single outpatient session, and discharged the same day
- Used commercial insurance (47.3%) or Medicare (32.3%) as their payor, with fewer than 5% self-pay or uninsured
- Were primarily diagnosed with metastatic disease to the liver (69.8%) but just over one-third (30.2%) had primary liver malignancies
- Colorectal cancer (26.7%) and pancreatic cancer (12.4%) led the types of primary tumors for those with metastatic disease
- Hepatocellular carcinoma (22.0%) and intrahepatic cholangiocarcinoma (8.2%) were most common types of primary liver cancer
Findings
On the positive side, 30-day readmission and emergency visits were quite low (both less than 1%), and the procedure showed low toxicity. One concerning finding was that 30-day mortality was 11.1% (108 patients), with no differences found between payer groups.
Practice Patterns
Researchers identified the following practice patterns:
- Public and commercial interest is outpacing high-quality comparative data. Published evidence for histotripsy is generally limited to small, single-center series, making its role in widely metastatic or advanced disease uncertain. In this study, the majority of the treatments (nearly 70%) were performed in patients with aggressive types of metastatic disease (e.g., pancreatic cancer), highlighting the need to better define which patients with metastatic disease are most likely to benefit from liver-directed treatment.
- Similar to chemotherapy, providing histotripsy within 30 days of death may warrant questioning whether it is being used for local disease control versus a heroic measure. Histotripsy is a procedure that was initially developed for local disease control. Despite its low procedural toxicity, the 11% mortality rate within 30 days indicates that patients may be receiving it as end-of-life care.
- Critical evaluation by surgical and medical oncologists, interventional radiologists, and hepatologist could improve patient selection while further evidence is gathered. New treatments should offer advantages for cancer control, survival, cost, or other outcomes. Although early clinical trials have demonstrated encouraging procedural safety and technical efficacy, proper patient selection data remain to be published.
“Our research raises important questions about patient selection as the adoption of histotripsy expands,” said Dr. Tsung. “Histotripsy is a promising technology, and prospective outcomes and comparative studies will be essential to define which patients are most likely to benefit and its appropriate role in multidisciplinary cancer care.”
See JAMA Network Open (Open Access)