Preliminary results of a phase I dose escalation clinical trial using focused ultrasound in the treatment of localised tumours

Abstract

Objective: The primary aim of this phase I trial was to assess the tolerance of cancer patients to focused ultrasound (FUS) treatment in a variety of different sites and to document any associated acute or delayed toxicity. This would appear to be the first time that treatment has been given without sedation or anaesthesia.

Methods: Patients with advanced and/or metastatic disease were eligible for entry into this study. Previous work has established that an in situ ablative intensity (AI) of 1500 W/cm2 Isp for 1 s achieves coagulative necrosis at the focal spot. Ultrasonic exposures of 25-100% of AI for 1 s were delivered to preselected tissue volumes. Pain questionnaires recording any side effects were completed by the patient and the investigator separately. Ultrasound images of the target volume were taken before, immediately after, and 1 week after treatment.

Results: A total of 14 patients have been entered into this study to date. Seven patients were treated at their primary site and seven received treatment to one of their metastases. No treatment needed to be stopped because of pain. Eight of the 14 patients did not complain of any side effect during or after the treatment. One patient complained of mild, and two of moderate pain during the week following treatment. One patient developed an asymptomatic blister on the skin.

Conclusion: Focused ultrasound is a safe, well-tolerated and non-invasive method of delivering ablative thermal energy to selected tumours. More clinical trials are needed to assess the role of this modality in the treatment of cancer.