Magnetic resonance-guided focused ultrasound treatment of extra-abdominal desmoid tumors: a retrospective multicenter study

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

MRgFUS ablation of a recurrent tenosynovial giant cell tumor in the foot using ExAblate 2100 system in combination with patient immobilization device

INTRODUCTION

Magnetic Resonance-guided Focused Ultrasound (MRgFUS) treatment for certain anatomy locations can be extremely challenging due to patient positioning and potential motion. This present study describes the treatment of a recurrent tenosynovial giant cell tumor of the plantar forefoot using the ExAblate 2100 system in combination with patient immobilization device.

METHODS

Prior to the treatment, several patient immobilization devices were investigated. Vacuum cushions were selected and tested for safety and compatibility with the treatment task and the MR environment.

RESULTS

During the treatment, one vacuum cushion immobilized the patient's right leg in knee flexion and allowed the bottom of the foot to be securely positioned on the treatment window. Another vacuum cushion supported the patient upper body extended outside the scanner bore. 19 sonications were successfully executed. The treatment was judged to be successful. No immediate complications were observed.

CONCLUSIONS

MRgFUS treatment of a recurrent tenosynovial giant cell tumor of the right plantar forefoot was successful with the use of patient immobilization vacuum cushions.

IMPLICATIONS FOR PRACTICE

The immobilization system could be utilized to aid future MRgFUS treatment of lesions in challenging anatomic locations. Various sizes of the vacuum cushions are available to potentially better accommodate other body parts and treatment configurations.

Update on musculoskeletal applications of magnetic resonance-guided focused ultrasound

Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive, incisionless, radiation-free technology used to ablate tissue deep within the body. This technique has gained increased popularity following FDA approval for treatment of pain related to bone metastases and limited approval for treatment of osteoid osteoma. MRgFUS delivers superior visualization of soft tissue targets in unlimited imaging planes and precision in targeting and delivery of thermal dose which is all provided during real-time monitoring using MR thermometry. This paper provides an overview of the common musculoskeletal applications of MRgFUS along with updates on clinical outcomes and discussion of future applications.

MR-guided focused ultrasound therapy of extra-abdominal desmoid tumors: a multicenter retrospective study of 105 patients

OBJECTIVE

To assess the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) for the treatment extra-abdominal desmoids.

METHODS

A total of 105 patients with desmoid fibromatosis (79 females, 26 males; 35 ± 14 years) were treated with MRgFUS between 2011 and 2021 in three centers. Total and viable tumors were evaluated per patient at last follow-up after treatment. Response and progression-free survival (PFS) were assessed with (modified) response evaluation criteria in solid tumors (RECIST v.1.1 and mRECIST). Change in Numerical Rating Scale (NRS) pain and 36-item Short Form Health Survey (SF-36) scores were compared. Treatment-related adverse events were recorded.

RESULTS

The median initial tumor volume was 114 mL (IQR 314 mL). After MRgFUS, median total and viable tumor volume decreased to 51 mL (95% CI: 30-71 mL, n = 101, p < 0.0001) and 29 mL (95% CI: 17-57 mL, n = 88, p < 0.0001), respectively, at last follow-up (median: 15 months, 95% CI: 11-20 months). Based on total tumor measurements (RECIST), 86% (95% CI: 75-93%) had at least stable disease or better at last follow-up, but 50% (95% CI: 38-62%) of remaining viable nodules (mRECIST) progressed within the tumor. Median PFS was reached at 17 and 13 months for total and viable tumors, respectively. NRS decreased from 6 (IQR 3) to 3 (IQR 4) (p < 0.001). SF-36 scores improved (physical health (41 (IQR 15) to 46 (IQR 12); p = 0.05, and mental health (49 (IQR 17) to 53 (IQR 9); p = 0.02)). Complications occurred in 36%, most commonly 1st/2nd degree skin burns.

CONCLUSION

MRgFUS reduced tumor volume, reduced pain, and improved quality of life in this series of 105 patients with extra-abdominal desmoid fibromatosis.

CLINICAL RELEVANCE STATEMENT

Imaging-guided ablation is being increasingly used as an alternative to surgery, radiation, and medical therapy for the treatment of desmoid fibromatosis. MR-guided high-intensity focused ultrasound is an incisionless ablation technique that can be used to reduce tumor burden effectively and safely.

KEY POINTS

• Desmoid fibromatosis was treated with MR-guided high-intensity focused ultrasound in 105 patients. • MR-guided focused ultrasound ablation reduced tumor volume and pain and improved quality of life. • MR-guided focused ultrasound is a treatment option for patients with extra-abdominal desmoid tumors.

High-Intensity Focused Ultrasound Surgery for Tumor Ablation: A Review of Current Applications

The management of cancer with alternative approaches is a matter of clinical interest worldwide. High-intensity focused ultrasound (HIFU) surgery is a noninvasive technique performed under US or MRI guidance. The most studied therapeutic uses of HIFU involve thermal tissue ablation, demonstrating both palliative and curative potential. However, concurrent mechanical bioeffects also provide opportunities in terms of augmented drug delivery and immunosensitization. The safety and efficacy of HIFU integration with current cancer treatment strategies are being actively investigated in managing primary and secondary tumors, including cancers of the breast, prostate, pancreas, liver, kidney, and bone. Current primary HIFU indications are pain palliation, complete ablation of localized earlystage tumors, or debulking of unresectable late-stage cancers. This review presents the latest HIFU applications, from investigational to clinically approved, in the field of tumor ablation. Keywords: Ultrasound, Ultrasound-High Intensity Focused (HIFU), Interventional-MSK, Interventional-Body, Oncology, Technology Assessment, Tumor Response, MR Imaging © RSNA, 2023.

Efficacy and safety of different thermal ablative therapies for desmoid-type fibromatosis: a systematic review and meta-analysis

Background

Desmoid-type fibromatosis (DF) is a locally aggressive tumor characterized by peripheral infiltration of neoplastic cells and remote metastasis disability. This systematic review examined the efficacy and safety of thermal ablative therapy for DF tumors.

Methods

A literature search was conducted using PubMed, Web of Science, Cochrane Library, and Embase from January 1, 2000, to November 12, 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used to guide literature selection. The inclusion criteria were the following: (I) the patients were diagnosed with aggressive fibromatosis pathologically, (II) the patients were treated by thermal ablations, and (III) a focus on treatment efficacy and safety. Meanwhile, the exclusion criteria were the following: (I) cohorts of patients with hypertrophic scar, Gardner fibroma, or nodular fasciitis; (II) conference abstracts, reviews, case reports, letters to editors, comments, or editorials; (III) number of patients <5; (IV) in vitro or animal experiments; and (V) non-English language articles. The inverse variance method with a random effects model was used to obtain the pooled data. Subgroup analyses were performed to identify treatment factors. Egger test was conducted to assess the risk of publication bias.

Results

After literature selection, 694 DF tumors were identified in 23 studies. In terms of modality, 13 studies used cryoablation, 9 studies used high-intensity focused ultrasound (HIFU), and 1 study used microwave ablation (MWA). The pooled symptom relief rate was 90% [95% confidence interval (CI): 80-97%], with that for HIFU being 100% (95% CI: 85-100%), that for cryoablation being 87% (95% CI: 74-97%), and that MWA being 89% (95% CI). The pooled major complication rate was 3% (95% CI: 1-7%), and that for each modality was as follows: HIFU =2% (95% CI: 0-6%), cryoablation =4% (95% CI: 1-8%), MWA =11%, ultrasound =6% (95% CI: 1-13%), computed tomography (CT) =2% (95% CI: 0-7%), and magnetic resonance imaging (MRI) =3% (95% CI: 0-14%). The pooled nonperfused volume rate (NPVR) was 76% (95% CI: 71-81%), and that for each modality was as follows: HIFU =77% (95% CI: 71-85%), cryoablation =74% (95% CI: 69-79%), ultrasound =75% (95% CI: 67-83%), CT =76% (95% CI: 67-87%), and MRI =78% (95% CI: 70-87%). The pooled local control rate was 88% (95% CI: 79-94%) and that for each modality was as follows: HIFU =99% (95% CI: 96-100%), cryoablation =80% (95% CI: 68-90%), and MWA =78%. The differences in major complication rate (P=0.77) and NPVR between imaging-guided modalities (P=0.40) were not significant, nor were the differences in symptom relief rate (P=0.32) and major complication rate (P=0.61) between ablative techniques; however, the differences in local control rate (P=0.01) were significant between ablative techniques.

Conclusions

Imaging-guided thermal ablative therapies contribute to symptom relief with a duration of more than 6 months and a low major complication rate of DF tumors.

Desmoid Tumors: A Comprehensive Review

Desmoid tumors (DT) are rare, locally aggressive, fibroblastic soft-tissue tumors that are characterized by infiltrative growth and can affect organs and adjacent structures, resulting in substantial clinical burden impacting patients' health-related quality of life. Searches of PubMed, Embase, Cochrane, and key conferences were conducted in November 2021 and updated periodically through March 2023 to identify articles describing the burden of DT. Of 651 publications identified, 96 relevant ones were retained. Diagnosis of DT is challenging because of its morphologic heterogeneity and variable clinical presentation. Patients visit multiple healthcare providers, often facing delays in correct diagnosis. The low incidence of DT (estimated 3-5 cases per million person-years) limits disease awareness. Patients with DT experience a high symptom burden: up to 63% of patients experience chronic pain, which leads to sleep disturbance (73% of cases), irritability (46% of cases), and anxiety/depression (15% of cases). Frequently mentioned symptoms are pain, limited function and mobility, fatigue, muscle weakness, and swelling around the tumor. Overall, quality of life in patients with DT is lower than in healthy controls. There is no treatment approved by the US Food and Drug Administration for DT; however, treatment guidelines reference available options, such as active surveillance, surgery, systemic therapy, and locoregional therapy. Choice of active treatment may depend on tumor location, symptoms, and risk of morbidity. The substantial burden of illness of DT is related to difficulties in timely and accurate diagnosis, high symptom burden (pain and functional limitations), and decreased quality of life. There is a high unmet need for treatments that specifically target DT and improve quality of life.

Current therapies and future prospective for locally aggressive mesenchymal tumors

Locally aggressive mesenchymal tumors comprise a heterogeneous group of soft tissue and bone tumors with intermediate histology, incompletely understood biology, and highly variable natural history. Despite having a limited to absent ability to metastasize and excellent survival prognosis, locally aggressive mesenchymal tumors can be symptomatic, require prolonged and repeat treatments including surgery and chemotherapy, and can severely impact patients' quality of life. The management of locally aggressive tumors has evolved over the years with a focus on minimizing morbid treatments. Extensive oncologic surgeries and radiation are pillars of care for high grade sarcomas, however, play a more limited role in management of locally aggressive mesenchymal tumors, due to propensity for local recurrence despite resection, and the risk of transformation to a higher-grade entity following radiation. Patients should ideally be evaluated in specialized sarcoma centers that can coordinate complex multimodal decision-making, taking into consideration the individual patient's clinical presentation and history, as well as any available prognostic factors into customizing therapy. In this review, we aim to discuss the biology, clinical management, and future treatment frontiers for three representative locally aggressive mesenchymal tumors: desmoid-type fibromatosis (DF), tenosynovial giant cell tumor (TSGCT) and giant cell tumor of bone (GCTB). These entities challenge clinicians with their unpredictable behavior and responses to treatment, and still lack a well-defined standard of care despite recent progress with newly approved or promising experimental drugs.

Case Report: Desmoid tumor response to magnetic resonance-guided high intensity focused ultrasound over 4 years

Desmoid tumors are a rare form of cancer, which show locally aggressive invasion of surrounding tissues and may occur anywhere in the body. Treatment options comprise conservative watch and wait strategies as tumors may show spontaneous regression as well as surgical resection, radiation therapy, nonsteroidal anti-inflammatory drugs (NSAID), chemotherapy, or local thermoablative approaches for progressive disease. The latter comprises cryotherapy, radiofrequency, microwave ablation, or thermal ablation with high intensity focused ultrasound (HIFU) as the only entirely non-invasive option. This report presents a case where a desmoid tumor at the left dorsal humerus was 2 times surgically resected and, after recurrence, thermally ablated with HIFU under magnetic resonance image-guidance (MR-HIFU). In our report, we analyze tumor volume and/or pain score during standard of care (2 years) and after HIFU treatment over a 4-year follow-up period. Results showed MR-HIFU treatment led to complete tumor remission and pain response.

Immunomodulation and targeted drug delivery with high intensity focused ultrasound (HIFU): Principles and mechanisms

High intensity focused ultrasound (HIFU) is a non-invasive and non-ionizing sonic energy-based therapeutic technology for inducing thermal and non-thermal effects in tissues. Depending on the parameters, HIFU can ablate tissues by heating them to >55 °C to induce denaturation and coagulative necrosis, improve radio- and chemo-sensitizations and local drug delivery from nanoparticles at moderate hyperthermia (~41-43 °C), and mechanically fragment cells using acoustic cavitation (also known as histotripsy). HIFU has already emerged as an attractive modality for treating human prostate cancer, veterinary cancers, and neuromodulation. Herein, we comprehensively review the role of HIFU in enhancing drug delivery and immunotherapy in soft and calcified tissues. Specifically, the ability of HIFU to improve adjuvant treatments from various classes of drugs is described. These crucial insights highlight the opportunities and challenges of HIFU technology and its potential to support new clinical trials and translation to patients.

Musculoskeletal oncology and thermal ablation: the current and emerging role of interventional radiology

The role of interventional radiology (IR) is expanding. With new techniques being developed and tested, this radiology subspecialty is taking a step forward in different clinical scenarios, especially in oncology. Musculoskeletal tumoral diseases would definitely benefit from a low-invasive approach that could reduce mortality and morbidity in particular. Thermal ablation through IR has already become important in the palliation and consolidation of bone metastases, oligometastatic disease, local recurrences, and treating specific benign tumors, with a more tailored approach, considering the characteristics of every patient. As image-guided ablation techniques lower their invasiveness and increase their efficacy while the collateral effects and complications decrease, they become more relevant and need to be considered in patient care pathways and clinical management, to improve outcomes. We present a literature review of the different percutaneous and non-invasive image-guided thermal ablation methods that are currently available and that could in the future become relevant to manage musculoskeletal oncologic diseases.

Role of the Interventional Radiologist in the Treatment of Desmoid Tumors

Desmoid tumors are locally aggressive soft tissue tumors with variable clinical presentation. As is the case with most relatively rare tumors, a multidisciplinary team approach is required to best manage these patients. Surgical resection, systemic therapy, and radiation therapy have classically been mainstays of treatment for desmoid tumors; however, a more conservative “wait-and-see” approach has been adopted given their high recurrence rates and significant morbidity associated with the aforementioned therapies. Given the challenges of classical treatment methods, interventional radiologists have begun to play a significant role in minimally invasive interventions for desmoid tumors. Herein, the authors review imaging characteristics of desmoid tumors, current management recommendations, and minimally invasive therapeutic intervention options.

A Pilot Study of Intralesional Injection of Triamcinolone Acetonide for Desmoid Tumors: Two-Year Outcomes

PURPOSE

The purpose of this pilot study was to examine the clinical efficacy and safety of serial triamcinolone injections for the treatment of desmoid tumors.

PATIENTS AND METHODS

Nine patients were enrolled into this prospective study and underwent three serial ultrasound-guided triamcinolone injections (120 mg) at 6-week intervals. MRI was compared at baseline and every 6 months, out to 24 months. Safety and tolerability were assessed by clinical evaluation and questionnaires, including the 12-item short form survey (SF-12), visual analog scale (VAS), and desmoid patient-reported outcome (PRO) tool.

RESULTS

At 24 months, 8 (88.9%) patients demonstrated a reduction in the volume of their tumor while 1 (11.1%) enlarged. Median tumor volume change was -26.9% (-81.1% to 34.6%; P = 0.055) All 9 tumors remained stable based on World Health Organization criteria, whereas 2 (22.2%) demonstrated partial response based on RECIST. There was a significant decrease in the tumor:muscle postcontrast mean signal intensity ratio at 6 months (P = 0.008) and 24 months (P = 0.004). There was a similar decrease in the tumor:muscle T2 mean signal intensity ratio at 24 months (P = 0.02). We found no difference in the SF-12 and VAS scores, but there were significant improvements in the desmoid PRO.

CONCLUSIONS

Treatment of desmoid tumors with serial triamcinolone injections appears safe and well tolerated by patients, with a 22% partial response based on RECIST. Further research is needed to confirm our results and determine factors predictive of response.

Aggressive gluteal fibromatosis: a rare case associated with spontaneous superior gluteal artery pseudoaneurysm

Deep fibromatosis is a locally aggressive neoplasm commonly involving the extremities. Several authors have described imaging features and complications associated with deep fibromatosis. We present the case of a 33-year-old man who presented with a right gluteal fibrous mass identified on magnetic resonance imaging (MRI), which was associated with a pseudoaneurysm originating from the right superior gluteal artery on serial follow-up with MRI and computed tomography. No intervention was done, and after conservative management, spontaneous thrombosis of the pseudoaneurysm was developed. Such imaging finding is the first report of a spontaneous development of pseudoaneurysm caused by deep fibromatosis, which could be a life-threatening condition and should be considered when dealing with deep fibromatosis and deciding on the appropriate treatment.

Large Desmoid Tumor of the Pancreas: A Report of a Rare Case and Review of the Literature

BACKGROUND Desmoid tumor (DT), also known as aggressive fibromatosis or desmoid-type fibromatosis, is a rare disease. It can occur in anyone at any age, and is more likely to appear in female patients. DTs are sometimes associated with familial adenomatous polyposis and rare syndromes such as Gardner syndrome. Arising from specific cells, fibroblasts, they tend to develop in patients with a history of abdominal surgery and rarely produce metastases. CASE REPORT We present a case of a 41-year-old man who was referred for abdominal discomfort with no digestive or general symptoms. An abdominal CT scan revealed a mass in the left hypochondrium, corresponding to an intraperitoneal tumor extending to left colon. Based on MRI, we suspected a gastrointestinal stromal tumor. Colonoscopy showed no intraluminal tumor in the colon. A PET-CT scan revealed tumor hypermetabolism and no metastases. The mass was diagnosed as a DT after percutaneous biopsy. Six weeks after diagnosis and as the tumor continued increasing despite pharmacological treatment, the patient underwent surgical pancreatic tail resection with splenectomy and left colonic segmentectomy. Histological examination revealed a 7.047-g DT with severe infiltration of pancreatic parenchyma and transmural colic barrier, with no high-grade differentiation and negative resection margins. The postoperative recovery was uneventful, and we proposed surveillance with MRI. CONCLUSIONS The DT was surgically removed and patient remains under MRI surveillance. Other reported management approaches consist of radiotherapy, tyrosine kinase inhibitors, anti-hormonal therapies/non-steroidal anti-inflammatory drugs, chemotherapy, or close surveillance only. This is, to our knowledge, the largest and heaviest DT reported in the modern literature.

The Role of Pharmacotherapeutic Agents in Children with Desmoid Tumors

Desmoid tumors (DT) are rare fibroblastic, soft-tissue tumors that do not metastasize but can aggressively infiltrate tissues causing significant chronic discomfort and/or functional impairment. In the pediatric population, the incidence of DT is greatest during infancy and adolescence but can occur at any age. Dysregulated β-catenin, most commonly resulting from mutations in either CTNNB1 or germline APC (adenomatous polyposis coli) drives DT. Most cases are sporadic but some are associated with predisposition syndromes such as familial adenomatous polyposis (FAP). Historically, treatment has been surgery. However, the recurrence rate after surgery can be high. Various systemic cytotoxic chemotherapy regimens used in other soft-tissue sarcomas have been applied to DT with differing results. Given the chronic and rarely life-threatening nature of this disease and the potential short- and long-term toxicity of these regimens, especially in children, alternative non-cytotoxic interventions have been investigated. Molecularly targeted agents such as tyrosine kinase and gamma secretase inhibitors have shown activity against DT. Innovative local control therapies are being employed as alternatives to surgery and radiation. Periods of prolonged stability and spontaneous regression in the absence of therapy in some patients has prompted wider adoption of an upfront active surveillance approach in the appropriate setting. This review will briefly summarize the epidemiology, pathophysiology, and clinical presentation of DT in children, then focus on historical, current, and future pharmacotherapeutic management and finally, propose areas for future study.

Interventional oncology: new techniques and new devices

Interventional oncology is a rapidly emerging field in the treatment of cancer. Minimally invasive techniques such as transarterial embolization with chemotherapeutic and radioactive agents are established therapies and are found in multiple guidelines for the management of primary and metastatic liver lesions. Percutaneous ablation is also an alternative to surgery for small liver, renal, and pancreatic tumors. Recent research in the niche of interventional oncology has focused on improving outcomes of established techniques in addition to the development of novel therapies. In this review, we address the recent and current advancements in devices, technologies, and techniques of chemoembolization and ablation: thermal ablation, histotripsy, high-intensity focused ultrasound, embolization strategies, liquid embolic agents, and local immunotherapy/antiviral therapies.

Management of unresectable and recurrent intra-abdominal desmoid tumors treated with ultrasound-guided high-intensity focused ultrasound: A retrospective single-center study

To assess the efficacy and safety of ultrasound (US)-guided high-intensity focused ultrasound (HIFU) ablation for treatment of unresectable and recurrent intra-abdominal desmoid tumors. From June 2014 to March 2020, 15 patients with consecutive unresectable and recurrent diseases that pathologically proven to be intra-abdominal desmoid tumors had undergone the treatment of US-guided HIFU ablation. All patients underwent contrast-enhanced magnetic resonance imaging before and after HIFU treatment. Nonperfused volume ratio was used to evaluate the effect of HIFU therapy. Intraprocedural and postprocedural adverse effects and complications are recorded to assess the safety of the therapy. Outcome of HIFU ablation has been investigated through serial contrast-enhanced imaging examinations during follow up. Out of 15 patients 14 of them have successfully completed the whole therapy, 1 patient is ineffective and gives up further treatment. The mean nonperfused volume ratio is 71.1% (95% confidence interval, 3% to 88.2%). During a mean follow up of 29 months (range from 8 to 61 months), the mean tumor volume was reduced by 59% (95% confidence interval, +49% to -100%). No tumor spreads along the treated area in all patients except one. Complications have occurred in 5 patients (33.3%), including bowel rupture (1 case), intra-abdominal abscess (1 case), slight injury to the femoral nerve (1 case), and bone injury (2 cases), the bowel rupture patient underwent surgery; the others have been cured during the follow up. US-guided HIFU ablation is an effective treatment modality for patients suffered from unresectable and recurrent intra-abdominal desmoid tumors.

Management of Patients with Newly Diagnosed Desmoid Tumors in a First-Line Setting

The initial management of desmoid tumors (DTs) is shifting from surgery towards active surveillance, with systemic and locally ablative treatments reserved for enlarging and/or symptomatic disease. However, it remains unclear which patients would benefit most from an initial conservative rather than interventional approach. To answer this question, we retrospectively analyzed adult and pediatric patients with DTs treated at a tertiary academic cancer center between 1992 and 2022. Outcomes measured were progression-free survival (PFS) and time to next treatment (TTNT) after first-line therapy. A total of 262 treatment-naïve patients were eligible for analysis with a median age of 36.5 years (range, 0−87 years). The 5-year PFS and the median TTNT (months) after first-line treatment were, respectively: 50.6% and 69.1 mo for surgery; 64.9% and 149.5 mo for surgery plus adjuvant radiotherapy; 57.1% and 44.7 mo for surgery plus adjuvant systemic therapy; 24.9% and 4.4 mo for chemotherapy; 26.7% and 5.3 mo for hormonal therapy; 41.3% and 29.6 mo for tyrosine kinase inhibitors (TKIs); 44.4% and 8.9 mo for cryoablation and high intensity focused ultrasound; and 43.1% and 32.7 mo for active surveillance. Age ≤ 40 years (p < 0.001), DTs involving the extremities (p < 0.001), a maximum tumor diameter > 60 mm (p = 0.04), and hormonal therapy (p = 0.03) predicted a higher risk of progression. Overall, our results suggest that active surveillance should be considered initially for patients with smaller asymptomatic DTs, while upfront TKIs, local ablation, and surgery achieve similar outcomes in those with more aggressive disease.

Multimodality Imaging Assessment of Desmoid Tumors: The Great Mime in the Era of Multidisciplinary Teams

Desmoid tumors (DTs), also known as desmoid fibromatosis or aggressive fibromatosis, are rare, locally invasive, non-metastatic soft tissue tumors. Although histological results represent the gold standard diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. Although histological analysis represents the gold standard for diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. DTs represent a challenge for the radiologist, being able to mimic different pathological conditions. A proper diagnosis is required to establish an adequate therapeutic approach. Multimodality imaging, including ultrasound (US), computed tomography (CT) and Magnetic Resonance Imaging (MRI), should be preferred. Different imaging techniques can also guide minimally invasive treatments and monitor their effectiveness. The purpose of this review is to describe the state-of-the-art multidisciplinary imaging of DTs; and its role in patient management.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

Transarterial Chemoembolization with Doxorubicin Eluting Beads for Extra-Abdominal Desmoid Tumors: Initial Experience

PURPOSE

To evaluate the feasibility, efficacy, and safety of doxorubicin-eluting bead transarterial chemoembolization (DEB-TACE) as an alternative local treatment for extra-abdominal desmoid tumors (DTs).

METHODS

Eleven adult female patients (mean age = 40.1 years) with symptomatic, progressively enlarging extra-abdominal DTs were determined ineligible for cryoablation after failing observation or systemic therapy and treated with a single session doxorubicin DEB-TACE. Six rectus sheath, one chest wall, three axilla, and one upper extremity DTs were included. The median follow-up was 155.0 ± 52.3 days. Treatment response was assessed by MRIs and maximum visual analog scale (VAS).

RESULTS

All procedures were technically successful without immediate complications. The average size of treated DT was 161.8 ml (range: 28.3-420.0 ml). The mean doxorubicin dose was 13.3 mg/m². All patients experienced skin changes which improved over time without treatments. No higher-grade adverse events were observed. Initial one-month follow-up MRI demonstrated partial to near-complete tumor necrosis, ranging from 1.4 to 97.6% (mean: 36.4%). Additional follow-up revealed a further reduction of overall tumor volume (mean: - 38.1%, p < 0.0001) and maximum VAS (mean: - 2.6, p = 0.0026) in 10 out of 11 patients (90.9%). After the first month, the residual tumors exhibited continued volume reduction in 10 out of 11 patients (mean:  - 16.5%, p = 0.0230). There was also a significant decrease of T2 signal intensity within residual tumor on the latest follow-up (mean:  - 29.6%, p = 0.0217), suggesting a reduction in tumor cellularity.

CONCLUSION

DEB-TACE may be a safe and effective local treatment alternative in DT patients.

Current management and recent progress in desmoid tumors

Desmoid tumors are rare soft tissue tumors that can have aggressive infiltrative growth and relapse locally. Desmoid tumors can impact functionality and cause treatment-related morbidity and mortality. Here, the authors review current management strategies and avenues for further investigation. As part of the evolution of therapy away from primary surgical approaches to less invasive options, image-guided ablation has been accepted as less morbid and include cryoablation and high-intensity focused ultrasound. Systemic therapy options currently include hormonal agents, nonsteroidal anti-inflammatory drugs, tyrosine kinase inhibitors, and anthracycline-based regimens. Hormonal agents and nonsteroidal anti-inflammatory drugs have benign side effect profiles but generally limited efficacy. Anthracycline-based therapies are limited by the risk of secondary malignancies and cardiomyopathy. Tyrosine kinase inhibitors are well studied, and sorafenib is now one of the most utilized therapies, though limited by its side effect profile. Nirogacestat (PF-0308401) is an investigational small molecule gamma-secretase (GS) inhibitor that has demonstrated efficacy in phase 1 and II trials. A phase III trial investigating patients with desmoid tumors or aggressive fibromatosis is estimated to be completed December 2021 (NCT03785964). In addition to nirogacestat, the gamma-secretase inhibitor AL102 is being investigated for the treatment of patients with progressing desmoid tumors in the phase II/III RINGSIDE trial. Finally, the beta-catenin inhibitor Tegavivint (BC2059) is being investigated in a phase 1 open-label trial in patients with a proven primary or recurrent desmoid tumor that is unresectable and symptomatic or progressive.

High-Intensity Focused Ultrasound Ablation for Postoperative Recurrent Desmoid Tumors: Preliminary Results

This study was aimed at evaluating the feasibility, safety and therapeutic effects of high-intensity focused ultrasound ablation (HIFUA) in the treatment of post-operative recurrent desmoid tumors. From September 2017 to May 2020, 42 consecutive patients with pathologically proven desmoid tumors treated with HIFUA for the first time were enrolled. These were divided into two groups: post-operative recurrent group (30 cases) and non-surgery group (12 cases). The basic characteristics, treatment parameters, ablation efficacy, tolerance and adverse events were recorded and compared between groups. The minimum distance between the tumor and skin surface in the post-operative recurrent group was significantly smaller than that in the non-surgery group (6.9 mm vs. 10.8 mm, p = 0.011), but there was no significant difference in the other basic characteristics (p > 0.05). The average acoustic power and intensity of treatment in the post-operative recurrent group were significantly lower than those in the non-surgery group (p = 0.006 and 0.036, respectively), but there was no significant difference in the remaining parameters or in ablation efficacy between groups (p > 0.05). HIFUA was successfully performed, and a large volume of coagulation necrosis was obtained from all patients without serious or life-threatening adverse events. Furthermore, there was no significant difference in the incidence of moderate adverse events and average length of stay between groups (p > 0.05). The average power and intensity of HIFUA treatment were adversely affected by surgical scar and tumor infiltration along the surgical path. However, HIFUA can still be used as an effective minimally invasive therapy for the local control of post-operative recurrent desmoid tumors.

The efficacy of low-power cumulative high-intensity focused ultrasound treatment for recurrent desmoid tumor

Background

Desmoid tumors are rare neoplasms that are locally invasive. However, optimal treatment strategies for recurrent desmoid tumors remain controversial. High‐intensity focused ultrasound (HIFU) has been reported as a noninvasive modality for treating recurrent desmoid tumors. However, its efficacy against massive desmoid tumors or those with complex anatomies remains unclear.

Methods

We developed a new therapeutic strategy called low‐power cumulative HIFU and applied it to treat recurrent desmoid tumors.

Results

We retrospectively collected data from 91 patients with recurrent desmoid tumors who underwent low‐power cumulative HIFU treatment after surgical treatment failure. The mean ablation proportion of the HIFU treatment was 69.5%, and the objective response rate was 47.3%. The 5‐year estimated progression‐free survival rate for these patients was 69.3%.

Conclusion

Low‐power cumulative HIFU treatment could achieve significant efficacy and long‐term control of recurrent desmoid tumors.

Focused Ultrasound for Pediatric Diseases

Focused ultrasound (FUS) is a noninvasive therapeutic technology with multiple pediatric clinical applications. The ability of focused ultrasound to target tissues deep in the body without exposing children to the morbidities associated with conventional surgery, interventional procedures, or radiation offers significant advantages. In 2021, there are 10 clinical pediatric focused ultrasound studies evaluating various musculoskeletal, oncologic, neurologic, and vascular diseases of which 8 are actively recruiting and 2 are completed. Pediatric musculoskeletal applications of FUS include treatment of osteoid osteoma and bone metastases using thermal ablation and high-intensity FUS. Pediatric oncologic applications of FUS include treatment of soft tissue tumors including desmoid tumors, malignant sarcomas, and neuroblastoma with high-intensity FUS ablation alone, or in combination with targeted chemotherapy delivery. Pediatric neurologic applications include treatment of benign tumors such as hypothalamic hamartomas with thermal ablation and malignant diffuse intrinsic pontine glioma with low-intensity FUS for blood brain barrier opening and targeted drug delivery. Additionally, low-intensity FUS can be used to treat seizures. Pediatric vascular applications of FUS include treatment of arteriovenous malformations and twin-twin transfusion syndrome using ablation and vascular occlusion. FUS treatment appears safe and efficacious in pediatric populations across many subspecialties. Although there are 7 Food and Drug Administration-approved indications for adult applications of FUS, the first Food and Drug Administration approval for pediatric patients with osteoid osteoma was obtained in 2020. This review summarizes the preclinical and clinical research on focused ultrasound of potential benefit to pediatric populations.

Cryotherapy in extra-abdominal desmoid tumors: A systematic review and meta-analysis

Introduction

Desmoid tumor is a locally-invasive neoplasm that causes significant morbidity. There is recent interest in cryotherapy for treatment of extra-abdominal desmoid tumors. This systematic review assesses evidence on safety and efficacy of cryotherapy in the treatment of extra-abdominal desmoid tumors.

Materials and methods

The systematic review was conducted with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Literature search was performed using MEDLINE and the Cochrane Central Register of Controlled Trials. 9 full text papers were reviewed and meta-analysis was performed for measures of safety, efficacy and symptom relief.

Results

The estimated pooled proportion of major and minor complications was 4.2% (95% CI, 1.8–9.6; I ² = 0%) and 10.2% (95% CI, 5.7–17.8; I ² = 0%) respectively. The estimated pooled proportion of non-progressive disease rate of all studies was 85.8% (95% CI, 73.4–93.0; I ² = 32.9%). The estimated progression free survival rate at 1 year was 84.5% (95% CI:74.6–95.8) and 78.0% at 3 years (95% CI: 63.8–95.3). As for pain control, the estimated pooled proportion of patients with decrease in visual analogue scale (VAS) > = 3 for those with VAS > = 3 before treatment for 2 studies was 87.5% (95% CI, 0.06–100; I ² = 71.5%) while 37.5% to 96.9% of patients were reported to have experienced partial or complete symptom relief in the other studies.

Conclusion

Cryotherapy is a safe and effective treatment modality for extra-abdominal desmoid tumors with efficacy similar to those treated with traditional strategies in the short to medium term.

Musculoskeletal Applications of Magnetic Resonance-Guided Focused Ultrasound

Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel noninvasive therapy that uses focused sound energy to thermally ablate focal pathology within the body. In the United States, MRgFUS is approved by the Food and Drug Administration for the treatment of uterine fibroids, palliation of painful bone metastases, and thalamotomy for the treatment of essential tremor. However, it has also demonstrated utility for the treatment of a wide range of additional musculoskeletal (MSK) conditions that currently are treated as off-label indications. Advantages of the technology include the lack of ionizing radiation, the completely noninvasive technique, and the precise targeting that offer unprecedented control of the delivery of the thermal dose, as well as real-time monitoring capability with MR thermometry. In this review, we describe the most common MSK applications of MRgFUS: palliation of bone metastases, treatment of osteoid osteomas, desmoid tumors, facet arthropathy, and other developing indications.

Feasibility of magnetic resonance-guided high-intensity focused ultrasound treatment targeting distinct nodular lesions in neurofibromatosis type 1

Background

Patients with Neurofibromatosis Type 1 (NF1) and plexiform neurofibromas (PN) often have radiographically diagnosed distinct nodular lesions (DNL) which can cause pain and weakness. Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) can precisely and accurately deliver heat to thermally ablate target tissue. The aim of this study is to evaluate whole-body MRIs from patients with NF1 and DNL, applying volumetrics and a consistent treatment planning approach to determine the feasibility of MR-HIFU ablation of DNL.

Methods

A retrospective review of whole-body MRI scans from patients with NF1 and PN from CNH and NCI was performed. DNL are defined as lesions >3 cm, distinct from PN and lacking the “central dot” feature. Criteria for MR-HIFU thermal ablation include target location 1–8 cm from skin surface; >1 cm from visible plexus, spinal canal, bladder, bowel, physis; and ability to ablate ≥50% of lesion volume. Lesions in skull and vertebral body were excluded.

Results

In 26 patients, 120 DNL were identified. The majority of DNL were located in an extremity (52.5%). Other sites included head/neck (7%), chest (13%), and abdomen/pelvis (28%). The predefined HIFU ablation criteria was not met for 47.5% of lesions (n = 57). The main limitation was proximity to a vital structure or organ (79%). Complete and partial HIFU ablation was feasible for 25% and 27.5% of lesions, respectively.

Conclusion

Based on imaging review of lesion location, technical considerations and ability to target lesions, thermal ablation with MR-HIFU may be a feasible noninvasive alternative for symptom management in patients with NF1 and symptomatic DNL.

Pseudoaneurysm within a desmoid tumor in an extremity: report of 2 cases

Desmoid tumor is considered a benign neoplasm, yet substantial morbidity can result from local invasion of structures adjacent to the tumor or from complications related to its treatment. We report two patients with extremity desmoid tumor who were each found at MRI to have an unsuspected pseudoaneurysm within their tumor after prior treatments (surgery and systemic therapy in one, surgery alone in the other). Such a pseudoaneurysm probably results from weakening of an arterial wall by adjacent desmoid tumor, as well as from local trauma. Due to the potential risk for life-threatening rupture of a pseudoaneurysm, one patient underwent surgical repair and the other, coil embolization. To our knowledge the presence of pseudoaneurysm has been reported within a few cases of abdominal desmoid tumor but not within an extremity desmoid tumor. This diagnosis has not been reported to have been made at MRI, either.

Breast Fibromatosis: Radiologic-Pathologic Correlation

Fibromatosis of the breast is a rare, benign locally infiltrative tumor without metastatic potential. Patients typically present with a painless, palpable, firm breast mass, which may be mobile or fixed to the pectoralis muscle. While some cases are related to familial mutations in the adenomatous polyposis coli (APC) gene, the majority are sporadic due to somatic mutations or prior injury to the breast tissue. On mammography, fibromatosis is typically seen as an irregular, dense, spiculated mass. US demonstrates a hypoechoic, irregular mass with indistinct margins. Fibromatosis is indistinguishable from breast cancer on imaging, and core biopsy is required for definitive diagnosis. Wide local excision is the historical standard for treatment; however, recurrence rates are high, and other emerging therapies are being explored. This article reviews the clinical features, imaging and histopathologic findings, along with brief overview of management.

The safety and ablation efficacy of ultrasound-guided high-intensity focused ultrasound ablation for desmoid tumors

OBJECTIVE

To evaluate the safety and efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for desmoid tumors (DTs).

METHOD

A total of 111 patients with histologically proven DTs were included and treated by USgHIFU ablation. Adverse events were continuously evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 until 3 months after treatment. The incidence of non-perfused areas within the treated tumors, non-perfused volume rate (NPVR) and tumor volume reduction were evaluated using contrast-enhanced MRI before and one week and 3 months after the procedure.

RESULTS

The enrolled patients (32 male, 79 female, mean age 29.5 ± 1.0 years) with 145 DTs (118 extra-abdominal, 16 abdominal wall, 11 intra-abdominal; median maximum diameter: 9.6 cm, range: 3-34.5 cm) underwent 188 sessions of HIFU ablation, and the mean number of ablations was 1.7 (range, 1-7) per patient. In majority of cases (143/145 cases, 98.6%), no serious adverse events were observed. There was no significant difference in the incidence of adverse events between patients who received a single treatment and those who received multiple treatments. Non-perfused area was observed within every treated tumor, and the median NPVR was 84.9% (range, 1.9-100%). The tumor volume reduction rate was 36.1 ± 4.2% at 3 months after treatment.

CONCLUSION

USgHIFU ablation, as a noninvasive and easily repeatable local treatment, is a promising treatment for DTs.

Musculoskeletal Oncologic Interventions: Proceedings from the Society of Interventional Radiology and Society of Interventional Oncology Research Consensus Panel

Musculoskeletal interventions are increasingly used with palliative and curative intent in the multidisciplinary treatment of oncology patients with bone and soft-tissue tumors. There is an unmet need for high-quality evidence to guide broader application and adoption of minimally invasive interventional technologies to treat these patients. Therefore, the Society of Interventional Radiology Foundation and the Society of Interventional Oncology collaborated to convene a research consensus panel to prioritize a research agenda addressing the gaps in the current evidence. This article summarizes the panel's proceedings and recommendations for future basic science and clinical investigation to chart the course for interventional oncology within the musculoskeletal system. Key questions that emerged addressed the effectiveness of ablation within specific patient populations, the effect of combination of ablation with radiotherapy and/or immunotherapy, and the potential of standardization of techniques, including modeling and monitoring, to improve the consistency and predictability of treatment outcomes.

A Single-Center 10-Year Retrospective Analysis of Cryoablation for the Management of Desmoid Tumors

PURPOSE

To determine the efficacy and safety of cryoablation in patients with desmoid tumors (DTs) retrospectively over a 10-year period at a single institution.

MATERIALS AND METHODS

Between February 25, 2010, and February 25, 2020, 25 patients (age, 12-80 years) with 26 lesions (mean preprocedural tumor volume was 237 cm³) were treated over 44 cryoablation procedures. Eleven patients were treated with first-line therapy. Fourteen patients had previous medical therapy, radiotherapy, and/or surgery. Subsequent clinical follow-up, imaging outcomes, and safety were analyzed for technical success, change in total lesion volume (TLV) and viable tumor volume (VTV), modified response evaluation criteria in solid tumors (mRECIST), progression-free survival (PFS) for tumor progression and symptom recurrence, symptom improvement, and procedure-related complications. Symptomatic improvement was defined as documentation of relief of pain (partial or complete) and/or functional impairment.

RESULTS

All procedures were technically successful. At 7-12 months, median changes in TLV and VTV were -6.7% (P = .809) and -43.7% (P = .01), respectively. At 10-12 months, the mRECIST responses were complete response, 0%; partial response, 61.5% (8/13); stable disease, 30.8% (4/13); and progressive disease, 7.7% (1/13). The median PFS for tumor progression and symptom recurrence were not reached, with a median follow-up of 15.3 and 21.0 months, respectively. Symptomatic relief (partial or complete) was achieved in 96.9% (32/33) of patients. One major complication was noted (2.4%).

CONCLUSIONS

In this retrospectively identified cohort, cryoablation was effective and safe for the local control of extra-abdominal DTs in short-term follow-up.

Advances in the Diagnosis and Management of Neonatal Sarcomas

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

High-intensity focused ultrasound treatment as an alternative regimen for myxofibrosarcoma

Myxofibrosarcoma is a common soft-tissue sarcoma in elderly patients, characterized by an infiltrative growth pattern and a high risk for persistent local recurrence. A 35-years-old woman was diagnosed with myxofibrosarcoma on the right upper arm and the tumor is surgically resected. The tumor relapsed 7 months later. Then the patient received five cycles of low power cumulative high-intensity focused ultrasound (HIFU) treatments, which completely ablated the tumor without complications. Now the patient is disease free with a high quality of life more than 30 months. This case indicates HIFU ablation might be a novel, promising therapy for recurrent myxofibrosarcoma.

Paediatric desmoid tumour of the head and neck: a complete response to chemotherapy and the paradigm shift towards non-surgical management

Desmoid tumours are rare locally aggressive mesenchymal tumours with a high local recurrence rate, particularly in the head and neck locations. We present the case of a 5-year-old child with a locally invasive inoperable desmoid tumour of the masticator space who underwent a low-dose chemotherapy regimen for 17 months, obtaining a long-term complete response. Definitive evidenced-based treatment guidelines are lacking. Therefore, paediatric patients should be managed by specialised multidisciplinary teams to try to achieve the best tumour control while minimising treatment associated morbidity and mortality. Available treatment options include surgery, radiotherapy and different systemic medical therapies. Whereas traditionally, surgery was the mainstay of treatment, more conservative options have increasingly shown adequate tumour control with little associated morbidity. In this decision making it is mandatory to take into account the patient's age, tumour location and extension, and potential short-term and long-term treatment-related sequelae to minimise functional and cosmetic compromise.

Experimental validation of acoustic and thermal modeling in heterogeneous phantoms using the hybrid angular spectrum method

PURPOSE

The aim was to quantitatively validate the hybrid angular spectrum (HAS) algorithm, a rapid wave propagation technique for heterogeneous media, with both pressure and temperature measurements.

METHODS

Heterogeneous tissue-mimicking phantoms were used to evaluate the accuracy of the HAS acoustic modeling algorithm in predicting pressure and thermal patterns. Acoustic properties of the phantom components were measured by a through-transmission technique while thermal properties were measured with a commercial probe. Numerical models of each heterogeneous phantom were segmented from 3D MR images. Cylindrical phantoms 30-mm thick were placed in the pre-focal field of a focused ultrasound beam and 2D pressure measurements obtained with a scanning hydrophone. Peak pressure, full width at half maximum, and normalized root mean squared difference (RMSDn) between the measured and simulated patterns were compared. MR-guided sonications were performed on 150-mm phantoms to obtain MR temperature measurements. Using HAS-predicted power density patterns, temperature simulations were performed. Experimental and simulated temperature patterns were directly compared using peak and mean temperature plots, RMSDn metrics, and accuracy of heating localization.

RESULTS

The average difference between simulated and hydrophone-measured peak pressures was 9.0% with an RMSDn of 11.4%. Comparison of the experimental MRI-derived and simulated temperature patterns showed RMSDn values of 10.2% and 11.1% and distance differences between the centers of thermal mass of 2.0 and 2.2 mm.

CONCLUSIONS

These results show that the computationally rapid hybrid angular spectrum method can predict pressure and temperature patterns in heterogeneous models, including uncertainties in property values and other parameters, to within approximately 10%.

Design and evaluation of an open-source, conformable skin-cooling system for body magnetic resonance guided focused ultrasound treatments

PURPOSE

Magnetic resonance guided focused ultrasound (MRgFUS) treatment of tumors uses inter-sonication delays to allow heat to dissipate from the skin and other near-field tissues. Despite inter-sonication delays, treatment of tumors close to the skin risks skin burns. This work has designed and evaluated an open-source, conformable, skin-cooling system for body MRgFUS treatments to reduce skin burns and enable ablation closer to the skin.

METHODS

A MR-compatible skin cooling system is described that features a conformable skin-cooling pad assembly with feedback control allowing continuous flow and pressure maintenance during the procedure. System performance was evaluated with hydrophone, phantom and in vivo porcine studies. Sonications were performed 10 and 5 mm from the skin surface under both control and forced convective skin-cooling conditions. 3D MR temperature imaging was acquired in real time and the accumulated thermal dose volume was measured. Gross analysis of the skin post-sonication was further performed. Device conformability was demonstrated at several body locations.

RESULTS

Hydrophone studies demonstrated no beam aberration, but a 5-12% reduction of the peak pressure due to the presence of the skin-cooling pad assembly in the acoustic near field. Phantom evaluation demonstrated there is no MR temperature imaging precision reduction or any other artifacts present due to the coolant flow during MRgFUS sonication. The porcine studies demonstrated skin burns were reduced in size or eliminated when compared to the control condition.

CONCLUSION

An open-source design of an MRgFUS active skin cooling system demonstrates device conformability with a reduction of skin burns while ablating superficial tissues.

Management of aggressive fibromatosis

Aggressive fibromatosis or desmoid tumor is a rare disease resulting from fibroblasts which do not metastasize. However, desmoid tumors belong to low-grade malignant tumors since they have high potential to infiltrate surrounding tissues, causing high local recurrence rates and may affect surrounding organs, threatening life quality and expectancy. Although surgery, watch and wait, radiotherapy, chemotherapy, high intensity focused ultrasound, ablation techniques or several agents have all been frequently investigated for the treatment of this type of disease, none are deemed as standard therapy for high recurrence rates that have been supported by any data. The present review retrieved literature on treatment options for desmoids to summarize the latest treatment modalities and refine their efficacy, as well as their side effects, in order to provide a more comprehensive treatment reference for clinicians.

Interventional Techniques for Bone and Musculoskeletal Soft Tissue Tumors: Current Practices and Future Directions - Part I. Ablation

Musculoskeletal (MSK) image-guided oncologic intervention is an established field within radiology. Numerous studies have described its clinical benefits, safety, cost effectiveness, patient satisfaction, and improved quality of life, thereby establishing image-guided oncologic intervention as a preferred pathway in treating patients presenting with specific benign MSK tumors. But there is a paradigm shift on the horizon because these techniques may also support established pillars (surgery, systemic treatment, radiotherapy) in the treatment of malignant MSK tumors. Unlike benign tumors, where they are used as primary therapy lines with curative intent, such interventions can be selected for malignant tumors as adjuvant treatment in painful or unstable bone or soft tissue lesions or as more palliative therapy strategies. Using examples from our clinical practices, we elaborate on the benefits of applying a multidisciplinary approach (traditionally involving MSK radiologists, oncologists, orthopaedic surgeons, microbiologists, pathologists, physiotherapists, and pain management experts), ideally within a sarcoma treatment center to deliver a patient-specific therapy plan and illustrate methods to assess the benefits of this model of care.In this article, we review the current repertoire of ablation techniques, demonstrate why such procedures offer value-based alternatives to conventional treatments of specific tumors, and reflect on future directions. Additionally, we review the advantages and limitations of each technique and offer guidance to improve outcomes.

NCCN Guidelines Insights: Soft Tissue Sarcoma, Version 1.2021

The NCCN Guidelines for Soft Tissue Sarcoma provide recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with soft tissue sarcomas. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including the development of a separate and distinct guideline for gastrointestinal stromal tumors (GISTs); reconception of the management of desmoid tumors; inclusion of further recommendations for the diagnosis and management of extremity/body wall, head/neck sarcomas, and retroperitoneal sarcomas; modification and addition of systemic therapy regimens for sarcoma subtypes; and revision of the principles of radiation therapy for soft tissue sarcomas.

Development and characterization of a tissue mimicking psyllium husk gelatin phantom for ultrasound and magnetic resonance imaging

Purpose: To develop and characterize a tissue-mimicking phantom that enables the direct comparison of magnetic resonance (MR) and ultrasound (US) imaging techniques useful for monitoring high-intensity focused ultrasound (HIFU) treatments. With no additions, gelatin phantoms produce little if any scattering required for US imaging. This study characterizes the MR and US image characteristics as a function of psyllium husk concentration, which was added to increase US scattering.Methods: Gelatin phantoms were constructed with varying concentrations of psyllium husk. The effects of psyllium husk concentration on US B-mode and MR imaging were evaluated at nine different concentrations. T1, T2, and T2* MR maps were acquired. Acoustic properties (attenuation and speed of sound) were measured at frequencies of 0.6, 1.0, 1.8, and 3.0 MHz using a through-transmission technique. Phantom elastic properties were evaluated for both time and temperature dependence.Results: Ultrasound image echogenicity increased with increasing psyllium husk concentration while quality of gradient-recalled echo MR images decreased with increasing concentration. For all phantoms, the measured speed of sound ranged between 1567-1569 m/s and the attenuation ranged between 0.42-0.44 dB/(cm·MHz). Measured T1 ranged from 974-1051 ms. The T2 and T2* values ranged from 97-108 ms and 48-88 ms, respectively, with both showing a decreasing trend with increased psyllium husk concentration. Phantom stiffness, measured using US shear-wave speed measurements, increased with age and decreased with increasing temperature.Conclusions: The presented dual-use tissue-mimicking phantom is easy to manufacture and can be used to compare and evaluate US-guided and MR-guided HIFU imaging protocols.

Are Current Technical Exclusion Criteria for Clinical Trials of Magnetic Resonance-Guided High-Intensity Focused Ultrasound Too Restrictive?: Early Experiences at a Pediatric Hospital

Certain technical criteria must be met to ensure the treatment safety of magnetic resonance-guided high-intensity focused ultrasound. We retrospectively reviewed how our enrollment criteria were applied from 2014 to 2017 in a clinical trial of magnetic resonance-guided high-intensity focused ultrasound ablation of recurrent malignant and locally aggressive benign solid tumors. Among the 36 screened patients between 2014 and 2017, more than one-third were excluded for technical exclusion criteria such as the anatomic location and proximity to prosthetics. Overall, patients were difficult to accrue for this trial, given the incidence of these tumors. To increase potential accrual, screening exclusion criteria could be more generalized and centered on the ability to achieve an acceptable treatment safety margin, rather than specifically excluding on the basis of general anatomic areas.

Rapid quantitative imaging of high intensity ultrasonic pressure fields

High intensity focused ultrasound (FUS) is a noninvasive technique for treatment of tissues that can lie deep within the body. There is a need for methods to rapidly and quantitatively map FUS pressure beams for quality assurance and accelerate development of FUS systems and techniques. However, conventional ultrasound pressure beam mapping instruments, including hydrophones and optical techniques, are slow, not portable, and expensive, and most cannot map beams at actual therapeutic pressure levels. Here, a rapid projection imaging method to quantitatively map FUS pressure beams based on continuous-wave background-oriented schlieren (CW-BOS) imaging is reported. The method requires only a water tank, a background pattern, and a camera and uses a multi-layer deep neural network to reconstruct two-dimensional root-mean-square (RMS) projected pressure maps that resolve the ultrasound propagation dimension and one lateral dimension. In this work, the method was applied to collect beam maps over a 3 × 1 cm2 field-of-view with 0.425 mm resolution for focal pressures up to 9 MPa. Results at two frequencies and comparisons to hydrophone measurements show that CW-BOS imaging produces high-resolution quantitative RMS projected FUS pressure maps in under 10 s, the technique is linear and robust to beam rotations and translations, and it can map aberrated beams.

High-intensity focused ultrasound ablation of muscle in an anticoagulated swine model

Introduction: Image-guided non-invasive high-intensity focused ultrasound (HIFU) has been gaining recognition in treating musculoskeletal tumors and desmoids. However, there is no consensus on the appropriate perioperative management for patients on ongoing anticoagulation who undergo HIFU ablation.Material and methods: Image-guided HIFU treatment was performed in swine on an ongoing oral anticoagulation protocol (N = 5) in two treatment sessions seven days apart. On day one, a total of twenty locations were ablated, and on day eight, ten more muscle ablations were performed, and the animals were euthanized. Imaging, clinical examination, and histopathology were performed to investigate treated tissue for bleeding.Results: Imaging, clinical examination, and histopathology revealed either no bleeding or, in some samples, only small scattered cavities (0.2-2 mm in diameter) filled with blood.Conclusion: Noninvasive HIFU ablation of muscle may not require a coagulation profile within normal limits.

Emerging clinical applications of high-intensity focused ultrasound

High-intensity focused ultrasound (HIFU) is a minimally-invasive and non-ionizing promising technology and has been assessed for its role in the treatment of not only primary tumors but also metastatic lesions under the guidance of ultrasound or magnetic resonance imaging. Its performance is notably effective in neurologic, genitourinary, hepato-pancreato-biliary, musculoskeletal, oncologic, and other miscellaneous applications. In this article, we reviewed the emerging technology of HIFU and its clinical applications.

Technology and precision therapy delivery in childhood cancer

PURPOSE OF REVIEW

The purpose of this review is to describe current advances in pediatric precision therapy through innovations in technology and engineering. A multimodal approach of chemotherapy, surgery and/or radiation therapy has improved survival outcomes for pediatric cancer but with significant early and late toxicities. The pediatric population is particularly vulnerable given their age during treatment. Advances in precision interventions discussed include image guidance, ablation techniques, radiation therapy and novel drug delivery mechanisms that offer the potential for more targeted approach approaches with improved efficacy while limiting acute and late toxicities.

RECENT FINDINGS

Image-guidance provides improved treatment planning, real time monitoring and targeting when combined with ablative techniques and radiation therapy. Advances in drug delivery including radioisotopes, nanoparticles and antibody drug conjugates have shown benefit in adult malignancies with increasing use in pediatrics. These therapies alone and combined may lead to augmented local antitumor effect while sparing systemic exposure and potentially limiting early and late toxicities.

SUMMARY

Pediatric cancer medicine often requires a multimodal approach, each with early and late toxicities. Precision interventions and therapies offer promise for more targeted approaches in treating pediatric malignancies and require further investigation to determine long-term benefit.

T2 mapping as a predictor of nonperfused volume in MRgFUS treatment of desmoid tumors

Objective: The objective of this study was to develop an alternative method of non-contrast monitoring of tissue ablation during focused ultrasound treatment. Desmoid tumors are benign but locally aggressive soft tissue tumors that arise from fibroblast cells. Magnetic resonance-guided focused ultrasound (MRgFUS) has emerged as an alternative to conventional therapies, showing promising results in reduction of tumor volume without significant side effects. The gold-standard assessment of the reduction of viable tumor volume post-treatment is non-perfused volume (NPV) and evaluation of NPV is typically performed with post-treatment gadolinium enhanced MR imaging. However, as gadolinium cannot be repeatedly administered during treatments, there is a need for alternative non-contrast monitoring of the tissue to prevent over and under treatment. Methods: Double-echo and multi-echo images were acquired before, during and after the MRgFUS treatment. T2 maps were generated with an exponential fit and T2 maps were compared to post-treatment post-contrast images.Results: In all five MRgFUS treatment sessions, T2 mapping showed excellent qualitative agreement with the post-contrast NPV.Conclusions: T2 mapping may be used to visualize the extent of ablation with focused ultrasound and can be used as a predictor of NPV prior to the administration of contrast during the post-treatment assessment.