HIFU Ablation of Soft Tissue Sarcoma

Around 3,300 people are diagnosed with soft tissue sarcoma (STS) each year in the UK, and a significant proportion of STS diagnoses are in people aged under 30 years. STS can arise from various tissue types and is comprised of over 50 tumour types. Although STS is treated with a combination of surgery, radiotherapy and chemotherapy, the prognosis is relatively poor with a five-year survival rate of 54%. There is an unmet need for further treatment modalities in STS.

High intensity focused ultrasound (HIFU) is a non-invasive way of treating cancers with minimal side effects, low complication rate and quick recovery. Ultrasound waves are used to destroy tumour cells and improvements in technology and experience are enabling complete destruction of tumour. HIFU also releases tumour antigens, increasing the immune response against cancer. HIFU has received FDA approvals for several indications, including bone metastases and we are using a CE-approved HIFU device in Oxford (UKCA-approvals anticipated for 2023). There have been some publications from China showing promise in STS, however this technology needs further evaluation within the UK's healthcare setting.

This study will recruit patients with both resectable and unresectable STS, in addition to unresectable small symptomatic desmoid tumours. 12-16 patients, and a minimum of 10 patients with malignant STS, will be treated over a maximum recruitment period of three years. HIFU treatment will be carried out as a day case procedure, and patients will be expected to be discharged home the same day.

The study is designed to generate evidence regarding safety and feasibility of HIFU for ablation of STS and intra-abdominal desmoids. In addition, the study is anticipated to provide information about the efficacy of HIFU against these tumour types which can help in the design of later phase studies. Short-term outcomes include feasibility, safety and the completeness of destruction of the tumour. Long-term outcomes include one-year survival, local recurrence and quality of life metrics (including pain scores). The study will also look at immunological response following ablation of STS using both blood and tumour samples pre- and post-HIFU ablation.