Feasibility of ExAblate MRI Guided High Intensity Focused Ultrasound Tx of Soft Tissue Tumors

Given that the incidence of cancer increases with age, the number of elderly patients
diagnosed and treated for soft tissue sarcomas (STS) will increase. The dilemma is that
surgeons and medical oncologists may be hesitant to treat elderly patients in a comparably
intensive manner as is used in the treatment of younger patients; factors such as decreased
performance status, significant comorbidities, and disease natural history may erode
enthusiasm for aggressive STS resection. To this end, a less invasive way of treating soft
tissue tumors would be helpful in younger patients to minimize morbidity and in the elderly
to provide less aggressive treatment options. The InSightec ExAblate 2000 magnetic
resonance-guided high-intensity focused ultrasound (MRgHIFU) system is a non-invasive thermal
ablation device fully integrated with an MR imaging system and used for the ablation of soft
tissue (5-10). The ExAblate combines a focused ultrasound surgery (FUS) delivery system and a
conventional diagnostic 1.5 T or 3 T MRI scanner. It provides a real-time therapy planning
algorithm, thermal dosimetry, and closed-loop therapy control.

INCLUSION CRITERIA

- ≥ 10 years of age.

- Benign or malignant soft tissue tumors of the extremities, flanks, pelvis, or
shoulders requiring surgical intervention.

- Tumor must not have been treated previously with radiation.

- Targeted tumor(s) are accessible to the ExAblate device

- Targeted volume within the tumor is located deeper than 1 cm from the skin

- Targeted tumor is clearly visible by non-contrast magnetic resonance imaging (MRI)

- Karnofsky Performance Status > 60

- Normal platelet count and coagulation profile

- Glomerular filtration rate > 60 mL/min

- Able to safely undergo MRI exam and receive mild sedation for the treatment.

- Able to tolerate being in the MRI scanner for the duration of the study.

- Able and willing to give consent (or consent + assent where applicable), and able to
attend all study visits.

EXCLUSION CRITERIA

- Previous radiation treatment to the tumor.

- Currently receiving dialysis.

- Acute medical condition (eg, pneumonia, sepsis) expected to hinder completion of the
study

- Unstable cardiac status including:

- Unstable angina pectoris on medication

- Patients with documented myocardial infarction within six months of protocol
entry

- Congestive heart failure requiring medication (other than diuretic)

- Patients on anti-arrhythmic drugs

- Severe hypertension (diastolic BP > 100 on medication)

- Contraindication for MR imaging such as implanted metallic devices that are not
MRI-safe, size limitations, etc

- Severe hematologic, neurologic, or other uncontrolled disease

- Known intolerance or allergy to medications used for sedation (midazolam), analgesia
(fentanyl), and local and regional anesthesia (lidocaine, bupivacaine, and
ropivacaine)

- Known intolerance or allergy to MR contrast agent (gadolinium chelates) including
advanced kidney disease

- Pregnant and nursing

- Karnofsky Performance Score < 60

- Severe cerebrovascular disease [cardiovascular accident (CVA) within 6 months]

- Not able or not willing to tolerate the required prolonged stationary position during
treatment (up to 5 hrs of total table time)

- Target volume in tumor is less than 1 cm from neurovascular bundles, major blood
vessels, bowel, or bladder.

- Targeted tumors:

- NOT visible by non-contrast MRI, OR

- NOT accessible to ExAblate device

- Not a candidate for either regional anesthesia or mild sedation

- Not be participating in another trial testing other investigational agents or devices