Key Points
- Researchers conducted a retrospective study of 105 patients who received focused ultrasound treatment for desmoid tumors.
- The focused ultrasound treatments lessened tumor volume, reduced pain, and improved quality of life.
Desmoid tumors can be rare, benign, aggressive, and painful growths that arise from connective tissue in various parts of the body. Although most desmoids spontaneously stabilize themselves, the ones that become aggressive are difficult to remove.
A collaborative group of researchers conducted a retrospective study of 105 patients who had undergone MR-guided focused ultrasound treatment of desmoid tumors. The team was primarily interested in assessing the safety and efficacy of the treatment. Pejman Ghanouni, MD, PhD, Andrew Dobrotwir, MBBS, and Matthew D. Bucknor, MD, were the principal investigators of the study, and the first author was Daniel M. Düx, MD, a research fellow funded by the Focused Ultrasound Foundation who completed his fellowship at Stanford University’s Minimally Invasive MRI-Guided Interventional Center (MIMRIC).
The group collected, reviewed, and analyzed data from 79 women and 26 men aged 21 to 49 years who were treated in the 10 years from 2011 through 2021 at Stanford’s MIMRIC, the University of California San Francisco, and at Future Medical Imaging Group in Melbourne, Australia. The treatments were performed using the Insightec Exablate body system.
“These three centers have the largest world experience treating desmoid tumors with MR-guided focused ultrasound,” said Dr. Ghanouni. “We learned through our collective experience how to address some of the technical issues of the procedure, for example, through the introduction of active skin cooling, which further improved our results.”
The outcome measures that they evaluated for each focused ultrasound treatment included tumor response (i.e., tumor volume changes), Progression Free Survival, changes in pain rating, quality of life, and treatment-related adverse events. They found that:
- At the patients’ last follow-up visit (15 months after treatment, on average), tumor size had decreased from a median volume of 114 milliliters before treatment to 51 milliliters after focused ultrasound, with a decrease in viable tumor volume to 29 milliliters.
- As much as 86% of the tumors were stable or decreased in size, but remaining viable tissue nodules within the tumor often grew.
- Median Progression Free Survival was reached at 17 months for total tumor volume and at 13 months for viable tumor nodules.
- Pain scores were significantly decreased (p < 0.001), from 6 to 3 on the numeric rating scale.
- Quality of life scores for physical and mental health both improved significantly.
- Complications, including first- and second-degree skin burns, occurred in 36% of the patients, mostly among patients early in the group’s experience.
The researchers concluded that focused ultrasound treatment for desmoid tumors reduced tumor volume, reduced pain, and improved quality of life in these patients, providing a safe and effective noninvasive treatment option.
“Because of technical restrictions, these treatments only targeted about 75% of the total tumor volume,” said Dr. Düx. “So, progression of the viable part of the untreated tumor was eventually seen in half of the patients; however, the untreated portions of the tumor most often grew by filling in the ablation cavity rather than growing into adjacent tissue. This explains the overall decrease in tumor size.”
When treating desmoid tumors, focused ultrasound could be a preferred option to surgery, which has a 35% failure rate; radiation, which has excellent tumor control (82%) but is less effective in younger patients and creates a risk of secondary malignancies, fractures, and neuropathy; or systemic therapy in the form of tyrosine kinase inhibitors, which take an average of 9.6 months for a response and can be accompanied by severe and mild complications (e.g., skin disorders, diarrhea, nausea).
Going forward, a major hurdle preventing the adoption of focused ultrasound for the treatment of desmoid tumors is reimbursement. Thanks to studies such as this one, the National Comprehensive Cancer Network® treatment guidelines were updated to include ablation – including with focused ultrasound – as an acceptable first-line option for the treatment of desmoid tumors.
“Reimbursement is certainly an issue for patients,” said Dr. Bucknor. “The challenge is that the course for many of these patients varies considerably by the location and extent of the tumor. If the patients were initially evaluated to see whether focused ultrasound ablation was an option for their tumor, they could then make a financial decision before they have scarring, procedures, and other treatments that might lessen the chance of success in the future.”
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