Feasibility of Desmoid Tumor Therapy Using MR-Guided HIFU at 3.0 Tesla: Initial Results on Safety, Local Tumor Control and Management

Abstract

Desmoid tumors are benign but locally aggressive soft tissue tumors formed by monoclonal proliferation of myofibroblasts. Traditional therapies (i.e. radical surgery, radiation, chemotherapy) in the treatment of are often unsatisfactory alone. Minimally invasive, and noninvasive techniques have been under great interest in recent years. The purpose of this study was to assess the feasibility, safety and local tumor control of magnetic resonance (MR) imaging guided high intensity focused ultrasound (HIFU) treatment of extra-abdominal desmoid tumors under 3.0 Tesla MRI-guidance. A total of 13 MR-HIFU treatments were performed using a Sonalleve MR-HIFU system with an in-table 0.8-1.4 MHz transducer with a 3 Tesla MR system. After the HIFU therapy, the MRI imaging sequence used for planning was repeated and the volume of non-perfused volume (NPV) of the tissue was used to assess treatment success. Clinical and MR-imaging follow-ups were carried out 1, 3, 6, and 12 months after the treatment. The HIFU ablation was successfully performed without major complications. The NPV percentage ranged from 0% to 95% after the initial treatment. Three patients experienced a regrowth of the viable tumor. Retreatments were performed to treat viable tumor tissue in four patients. In one patient, MR-HIFU treatments were practically unsuccessful. At the final follow-up, the NPV of the desmoid tumors ranged from 6% to 91%. In conclusion, MR-HIFU is safe and effective technique in treatment of extra-abdominal desmoid tumors. More research is needed to understand varying behavior of different desmoid tumors to improve patient selection for different therapies and treatments.