HK pioneers histotripsy in Asia for liver tumours

Hong Kong has become the first in Asia to introduce histotripsy – a nonthermal, nonionizing, noninvasive, focused ultrasound technique that induces cavitation and mechanical destruction of tissue at a focal point – for treatment of liver tumours in clinical trials.

This innovation is made possible through donations from the Li Ka Shing Foundation to the two medical schools in Hong Kong. The first histotripsy system was introduced at the University of Hong Kong (HKU) in August 2024, while the second system will be available at the Chinese University of Hong Kong (CUHK) by the end of the year.

The donations also support 10 patients to receive histotripsy treatment in a clinical trial at the Queen Mary Hospital (QMH) and another 10 patients to receive the treatment in CUHK’s clinical trial.

HKU’s clinical trial – the first clinical trial of histotripsy in Asia – enrols patients with hepatocellular carcinoma (HCC) or metastatic liver tumours, including those who need bridging treatment to maintain disease control while awaiting liver transplantation. The inclusion criteria are tumour size <5 cm, adequate liver function, and ability to tolerate general anaesthesia.

“Histotripsy involves the application of focused ultrasound waves on cancer cells to form microbubbles within the tumour. This leads to rapid cell expansion and collapse, generating mechanical waves that break and liquefy targeted tumour cells,” said Professor Albert Chan of the Department of Surgery, HKU, who leads the HKU trial.

“Histotripsy may offer an alternative to surgical resection in patients with liver tumours who are not candidates for surgery,” Chan continued. “The histotripsy lysate is rapidly reabsorbed after the procedure. Postprocedure recovery is fast. Only about 1–2 days of hospitalization is required.”

In the US, histotripsy received FDA authorization in October 2023 for noninvasive destruction of liver tumours, including unresectable liver tumours, based in part on data from the multicentre #HOPE4LIVER trials conducted in the US and Europe in patients with primary or secondary liver tumours. [https://ascopost.com/news/october-2023/fda-grants-marketing-authorization-to-edison-histotripsy-system-for-treatment-of-liver-tumors; Radiology 2024;312:e233051] Since then, nearly 400 patients have undergone histotripsy treatment in the US. No local recurrences of targeted tumours or procedure-related major complications have been reported.

In the pivotal #HOPE4LIVER trials, 44 patients (21 from the US, 23 from Europe; mean age, 63.9 years; female, 50 percent; HCC, 41 percent; non-HCC liver metastases, 59 percent) with 49 tumours were treated with histotripsy during a single procedure (mean treatment time, 34 minutes; total procedure duration, 221 minutes). The technical success rate of tumour treatment was 95 percent, and procedure-related major complications within 30 days were reported in 7 percent of patients, which met the trial’s performance goals for these coprimary endpoints of >70 percent and <25 percent, respectively. [Radiology 2024;312:e233051]

“We will also evaluate histotripsy’s effects on the immune system to pave the way for combining histotripsy with immunotherapy in the future,” said Chan.