“Ask Dr. HKSH” - Non-invasive Histotripsy

Dr. CHAN See Ching

Specialist in General Surgery

Q1. What is Non-invasive Histotripsy?

As a groundbreaking treatment for liver cancer, Histotripsy can generate and focus high-intensity ultrasound on target tumours. Microbubbles are created within the tumours, and through rapid expansion and collapse, generates shockwaves to destroy and liquefy cancer cells. Guided in real-time by advanced ultrasound imaging technology, this treatment can target tumours with high precision while minimising damage to the surrounding healthy liver tissues.

Q2. What are the advantages of Histotripsy?

This technology is non-invasive. It does not involve radiation, thermal energy, or needle insertion. Trauma is minimal. As the treatment focuses on the tumour area with minimal impact to the surrounding tissues, it means quicker recovery for patients. It also causes no pain and scars after treatment, thus allowing patients to resume normal life and work sooner, or continue with other treatments if needed.

Q3. Which patients are suitable for Histotripsy treatment?

Non-invasive Histotripsy is suitable for patients with primary or metastatic liver cancer, especially if they are considered not suitable for surgery or have not responded well to other treatments.

In terms of tumour characteristics, this treatment is recommended for patients with a small number of tumours of around 2 to 3 cm in diameter. If there are more than three tumours, a single session may not suffice. There are also limitations due to tumour location. If the tumours are located too high in the liver, close to the diaphragm, or near the underside of the heart, it may fail to be treated in its entirety due to angle limitations, making Histotripsy not a suitable treatment option. In addition, tumours located beneath the ribs may prevent the energy from reaching the target effectively, also making Histotripsy unsuitable in such cases.

Q4. Is special preparation necessary before treatment?

Before treatment, basic assessments are conducted for general health and tumour location. As mentioned above, the locations of certain tumour may make them not amenable to Histotripsy treatment. An ultrasound examination is thus necessary to pinpoint the tumour, and determine if it can be targeted with precision before treatment begins. In general, Histotripsy is suitable for a wide range of patients – it is well tolerated by most patients except for those with certain lung problems. Patients with mild heart conditions or relatively poor liver function are still suitable for treatment.

Q5. How is the Histotripsy treatment performed?

The entire treatment procedure is performed under general anaesthesia, as the patient must remain completely still during treatment. Breathing is also carefully controlled during anaesthesia to prevent deep or excessive movement. As the liver is located beneath the lungs, large breathing movements may affect the accuracy of the focus. A specialised anaesthetic approach is thus adopted by placing a small water tank over the patient’s abdominal cavity during treatment. Energy is emitted through the water tank and targeted at the liver tumour inside the body, causing disruption to the cancer cells.

Q6. When can patients be discharged?

Patients are usually admitted to the hospital in the morning, and scheduled for treatment in the afternoon. After the procedure, patients will remain in hospital overnight for rest and observation. Further assessment and routine blood tests will be performed the next morning, and patients will be discharged if all indicators are normal, including liver function, kidney function, haemoglobin level, and white blood cell count.

During this period, patients may develop a mild fever. The destruction of cancer cells may trigger an immune response, as the body clears away the fragmented tissues and activates its own immune system to fight the remaining cancer cells. In fact, patients can return home to rest as the resulting fever is mild. It should not be a cause for concern.

Q7. If I am deemed unsuitable for Histotripsy after consultation, what other options are available?

If one’s physical condition or tumour condition is not suitable for Histotripsy, our medical team will recommend the most appropriate treatment options after detailed review, such as surgery, interventional procedures, radiotherapy (including proton therapy), immunotherapy, etc. An individualised treatment plan will be formulated based on each patient’s needs.