High-intensity focused ultrasound treatment for advanced pancreatic cancer

Initial treatment for surgery-naïve desmoid tumors by high intensity focused ultrasound

Introduction

Desmoid tumor (DT) is a rare proliferative disease occurring in connective tissues, characterized by high infiltration and recurrence rates. While surgery remains the primary treatment, its recurrence risk is high, and some extra-abdominal desmoid tumors are inoperable due to their locations. Despite attempts with radiotherapy and systemic therapy, the efficacy remains limited.

Methods

We used low-power cumulative high-intensity focused ultrasound (HIFU) therapy as an initial treatment for desmoid tumor patients either ineligible or unwilling for surgery. Low-power cumulative HIFU employs slower heat accumulation and diffusion, minimizing damage to surrounding tissues while enhancing efficacy.

Results

Fifty-seven non-FAP desmoid tumor patients, previously untreated surgically, underwent low-power cumulative HIFU therapy. Among them, 35 had abdominal wall DT, 20 had extra-abdominal DT, and 2 had intra- abdominal DT, with an 85% median ablation ratio. Abdominal wall DT patients showed significantly better response rates (91.4% vs. 86%) and disease control rates (100% vs. 32%) than that of non-abdominal wall DT patients. Median event- free survival time was not reached after a median follow-up duration of 34 months.

Discussion

With its high response rate, durable efficacy, and mild adverse effects, our findings suggest that low-power cumulative HIFU presents a promising novel treatment for desmoid tumors, particularly abdominal wall DT patients.

Repeated high‑intensity focused ultrasound combined with iodine‑125 seed interstitial brachytherapy offers improved quality of life and pain control for patients with advanced pancreatic cancer: A 52‑patient retrospective study

Patients diagnosed with pancreatic cancer who have 5-year survival rates of ~5% are typically in the advanced stage. Pancreatic cancer has become the third leading cause of cancer-related death in the United States and there is still a lack of effective treatments to improve patient survival rate. Hence, the purpose of the present retrospective study was to assess the potential clinical impact of repeated high-intensity focused ultrasound (HIFU) combined with iodine-125 (125I) interstitial brachytherapy for the treatment of patients with advanced pancreatic cancer who were ineligible for or declined surgery and chemotherapy. A total of 52 patients diagnosed with advanced pancreatic cancer were included in the study. At least one course of HIFU therapy combined with percutaneous ultrasound-guided 125I seed implantation was administered to each patient. The clinical assessment included an evaluation of Karnofsky Performance Scale (KPS) score at baseline, and at 1 and 2 months after combined therapy. Pain intensity was additionally evaluated with the numerical rating score (NRS). Overall survival (OS) times and survival rates at 3, 6, 9 and 12 months after combined treatment were evaluated. Adverse events commonly associated with HIFU and 125I seed implantation were recorded, and the severity of adverse events was graded according to the Common Terminology Criteria for Adverse Events, version 4. All 52 patients received successful repeated HIFU treatment combined with 125I seed implantation and were included in the analysis of efficacy and safety. The median OS time of patients was estimated to be 13.1 months (95% CI, 11.3-14.8). The survival rates at 3, 6, 9 and 12 months were 100.0, 86.5, 61.5 and 53.8%, respectively. The mean KPS score was 62.7±6.3 at baseline, 73.7±7.9 at 1 month and 68.8±6.5 at 2 months after combined treatment. KPS score increased significantly after combined therapy. The mean NRS score was 6.7±1.6 at baseline, and 4.7±1.7 and 5.4±1.5 at 1 and 2 months after combined treatment, respectively. The number of patients with severe pain and the NRS score were both significantly lower at 1 and 2 months after 125I seed implantation compared with those at baseline. No serious complications were detected during the follow-up period. In conclusion, the present study demonstrated the survival benefit and improvement in quality of life of patients with advanced pancreatic cancer receiving repeated HIFU treatment combined with 125I interstitial brachytherapy, which may provide new ideas and methods for the treatment of pancreatic cancer.

An Emerging Era: Conformable Ultrasound Electronics

Conformable electronics are regarded as the next generation of personal healthcare monitoring and remote diagnosis devices. In recent years, piezoelectric-based conformable ultrasound electronics (cUSE) have been intensively studied due to their unique capabilities, including nonradiative monitoring, soft tissue imaging, deep signal decoding, wireless power transfer, portability, and compatibility. This review provides a comprehensive understanding of cUSE for use in biomedical and healthcare monitoring systems and a summary of their recent advancements. Following an introduction to the fundamentals of piezoelectrics and ultrasound transducers, the critical parameters for transducer design are discussed. Next, five types of cUSE with their advantages and limitations are highlighted, and the fabrication of cUSE using advanced technologies is discussed. In addition, the working function, acoustic performance, and accomplishments in various applications are thoroughly summarized. It is noted that application considerations must be given to the tradeoffs between material selection, manufacturing processes, acoustic performance, mechanical integrity, and the entire integrated system. Finally, current challenges and directions for the development of cUSE are highlighted, and research flow is provided as the roadmap for future research. In conclusion, these advances in the fields of piezoelectric materials, ultrasound transducers, and conformable electronics spark an emerging era of biomedicine and personal healthcare.

Locoregional Therapies and Remodeling of Tumor Microenvironment in Pancreatic Cancer

Despite the advances made in treatment, the prognosis of pancreatic ductal adenocarcinoma (PDAC) remains dismal, even in the locoregional and locally advanced stages, with high relapse rates after surgery. PDAC exhibits a chemoresistant and immunosuppressive phenotype, and the tumor microenvironment (TME) surrounding cancer cells actively participates in creating a stromal barrier to chemotherapy and an immunosuppressive environment. Recently, there has been an increasing use of interventional radiology techniques for the treatment of PDAC, although they do not represent a standard of care and are not included in clinical guidelines. Local approaches such as radiation therapy, hyperthermia, microwave or radiofrequency ablation, irreversible electroporation and high-intensity focused ultrasound exert their action on the tumor tissue, altering the composition and structure of TME and potentially enhancing the action of chemotherapy. Moreover, their action can increase antigen release and presentation with T-cell activation and reduction tumor-induced immune suppression. This review summarizes the current evidence on locoregional therapies in PDAC and their effect on remodeling TME to make it more susceptible to the action of antitumor agents.

High Intensity Focused Ultrasound Ablation for Patients With Locally Advanced Pancreatic Adenocarcinoma: A Propensity Score-Matching Analysis

OBJECTIVES

This retrospective study was conducted to assess the efficacy and safety of high intensity focused ultrasound (HIFU) in combination with chemotherapy compared with chemotherapy alone in treating patients with unresectable locally advanced pancreatic cancer (LAPC).

METHODS

The data of unresectable LAPC patients who received chemotherapy with or without HIFU ablation were retrieved retrospectively. The overall survival (OS), objective response rate (ORR), cancer antigen 19-9 response rate, and safety were compared between these two groups before and after propensity score matching (PSM).

RESULTS

Overall, 254 patients with LAPC were included, of whom 92 underwent HIFU ablation. After PSM to control for potential biases, HIFU was associated with improved OS (12.8 versus 12.2 months, log-rank P = .046), as compared to patients without HIFU ablation. Patients with numeric rating scale (NRS) less than 4, and receiving HIFU ablation were significantly associated with improved OS (adjusted hazard ratio [aHR] = 0.365 [95% confidence interval (CI) = 0.148-0.655], P = .002; aHR = 0.490 [95% CI = 0.250-0.961], P = .038; respectively) by multivariate analyses with the adjustment of age, NRS, and tumor size. ORR was also observed to be higher in HIFU group of 30.0% than in the chemotherapy group of 13.3% (P = .039). No severe adverse events of special interest or HIFU-caused deaths were observed.

CONCLUSIONS

Patients with unresectable LAPC who received gemcitabine-based chemotherapy might benefit from additional HIFU ablation.

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.

Long survival in a pancreatic carcinoma patient with multi-organ toxicities after sintilimab treatment: A case report

Pancreatic carcinoma is the leading cause of death among digestive malignancies in China. In particular, there is no breakthrough in prolonging the survival of pancreatic cancer patients with chemical and targeted therapies. Tumor immunotherapy brings opportunities and progress for the treatment of pancreatic cancer. Sintilimab is an innovative PD-1 inhibitor which was reported certain clinical benefits in multi-line treatments of advanced pancreatic cancer with gemcitabine. The combination therapy of PD-1 with gemcitabine plus high-intensity focused ultrasound (HIFU) in pancreatic cancer has not been reported. Here we report a case of a Chinese old patient diagnosed with metastatic pancreatic cancer. Two months after sintilimab treatment, the patient occurred severe immune colitis. The patient was diagnosed with immune ureteritis after 8 months of treatment. The immue-related adverse events (irAEs) refined after timely recognition and correct intervention by the clinician and clinical pharmacist. After first-line treatment of sintilimab plus gemcitabine combined with pancreatic HIFU, the patient achieved a remarkable benefit of 11-month progression-free survival (PFS) and 20-month overall survival (OS). The first-line treatment of sintilimab plus gemcitabine combined with HIFU demonstrates a potential therapeutic effect on metastatic pancreatic carcinoma with tolerable adverse reactions.

Effects of human tissue acoustic properties, abdominal wall shape, and respiratory motion on ultrasound-mediated hyperthermia for targeted drug delivery to pancreatic tumors

Background

PanDox is a Phase-1 trial of chemotherapeutic drug delivery to pancreatic tumors using ultrasound-mediated hyperthermia to release doxorubicin from thermally sensitive liposomes. This report describes trial-related hyperthermia simulations featuring: (i) new ultrasonic properties of human pancreatic tissues, (ii) abdomen deflections imposed by a water balloon, and (iii) respiration-driven organ motion.

Methods

Pancreas heating simulations were carried out using three patient body models. Pancreas acoustic properties were varied between values found in the literature and those determined from our human tissue study. Acoustic beam distortion was assessed with and without balloon-induced abdomen deformation. Target heating was assessed for static, normal respiratory, and jet-ventilation-controlled pancreas motion.

Results

Human pancreatic tumor attenuation is 63% of the literature values, so that pancreas treatments require commensurately higher input intensity to achieve adequate hyperthermia. Abdominal wall deformation decreased the peak field pressure by as much as 3.5 dB and refracted the focal spot by as much as 4.5 mm. These effects were thermally counteracted by sidelobe power deposition, so the net impact on achieving mild hyperthermia was small. Respiratory motion during moving beam hyperthermia produced localized regions overheated by more than 8.0 °C above the 4.0 °C volumetric goal. The use of jet ventilation reduced this excess to 0.7 °C and yielded temperature field uniformity that was nearly identical to having no respiratory motion.

Conclusion

Realistic modeling of the ultrasonic propagation environment is critical to achieving adequate mild hyperthermia without the use of real time thermometry for targeted drug delivery in pancreatic cancer patients.

High-intensity focused ultrasound therapy for pancreatic cancer

Pancreatic cancer (PC) has one of the poorest prognoses among solid cancers, and its incidence has increased recently. Satisfactory outcomes are not achieved with current therapies; thus, novel treatments are urgently needed. High-intensity focused ultrasound (HIFU) is a novel therapy for ablating tissue from the outside of the body by focusing ultrasonic waves from multiple sources on the tumor. In this therapy, only the focal area is heated to 80-100 ºC, which causes coagulative necrosis of the tissue, with hardly any impact on the tissue outside the focal area. Although HIFU is a minimally invasive treatment and is expected to be useful, it is not yet generally known. Here, we discuss the usefulness of HIFU treatment for un-resectable advanced PC using the results of previous research, meta-analyses, and systematic reviews on its efficacy and safety. HIFU therapy for un-resectable PC is useful for its anti-tumor effect and pain relief, and is expected to prolong survival time and improve quality of life. Although HIFU for PC has several limitations and further study is needed, this technique can be safely performed on un-resectable advanced PC. In future, HIFU could be utilized as a minimally invasive treatment strategy for PC patients with a poor prognosis.

Ultrasounds in cancer therapy: A summary of their use and unexplored potential

Ultrasounds (US) are a non-ionizing mechanical wave, with less adverse effects than conventional pharmacological or surgical treatments. Different biological effects are induced in tissues and cells by ultrasound actuation depending on acoustic parameters, such as the wave intensity, frequency and treatment dose. This non-ionizing radiation has considerable applications in biomedicine including surgery, medical imaging, physical therapy and cancer therapy. Depending on the wave intensity, US are applied as high-intensity ultrasounds (HIUS) and low-intensity pulsed ultrasounds (LIPUS), with different effects on cells and tissues. HIUS produce thermal and mechanical effects, resulting in a large localized temperature increase, leading to tissue ablation and even tumor necrosis. This can be achieved by focusing low intensity waves emitted from different electrically shifted transducers, known as high-intensity focused ultrasounds (HIFU). LIPUS have been used extensively as a therapeutic, surgical and diagnostic tool, with diverse biological effects observed in tissues and cultured cells. US represent a non-invasive treatment strategy that can be applied to selected areas of the body, with limited adverse effects. In fact, tumor ablation using HIFU has been used as a curative treatment in patients with an early-stage pancreatic tumor and is an effective palliative treatment in patients with advanced stage disease. However, the biological effects, dose standardization, benefit-risk ratio and safety are not fully understood. Thus, it is an emerging field that requires further research in order to reach its full potential.

A meta-analysis evaluating the role of high-intensity focused ultrasound (HIFU) as a fourth treatment modality for patients with locally advanced pancreatic cancer

BACKGROUND

This study aimed to evaluate the outcomes of high-intensity focused ultrasound (HIFU) on patients with advanced pancreatic cancer.

METHODS

A literature search was performed in PubMed, Scopus and Cochrane databases, in accordance with the PRISMA guidelines. The Odds Ratio, Weighted Mean Difference, and 95% Confidence Interval were evaluated by means of the Random-Effects model.

RESULTS

Nineteen articles met the inclusion criteria, incorporating 939 patients. This study reveals that patients in the HIFU group presented increased median overall survival (OS), along with higher OS at 6 and 12 months after treatment compared with the control group (p < 0.05). Furthermore, patients treated with HIFU in conjunction with chemotherapy presented reduced levels of pain (p < 0.05) compared to the traditional treatment group. In addition, HIFU contributed to significant tumor responsiveness, in terms of CA19-9 reduction (p < 0.05). Finally, HIFU was a considerably safe treatment modality with a low incidence of complications.

CONCLUSION

These outcomes suggest that HIFU is a feasible and safe treatment modality for patients with advanced pancreatic cancer and provides enhanced outcomes regarding survival and quality of life. Given the lack of a significant number of randomized clinical trials, this meta-analysis represents the best currently available evidence. New randomized trials assessing HIFU are necessary to further evaluate their outcomes.

Quasi-Bessel Acoustic-Vortex Beams Constructed by the Line-Focused Phase Modulation for a Ring Array of Sectorial Planar Transducers

Acoustic Bessel beams are commonly used as ideal sources to study the characteristics for acoustic-vortex (AV) beams, exhibiting prosperous perspectives in contactless object manipulations and acoustic communications. However, accurate Bessel beams are difficult to construct using 2-D arrays in practical applications. By integrating active phase control and passive phase modulation to a ring array of sectorial planar transducers, quasi-Bessel AV (QB-AV) beams of arbitrary order are built by the line focus of AV fields in the current study. Based on Snell's refraction law, a circular sawtooth lens of phase modulation is designed to converge incident waves toward the beam axis at the same deflection angle. QB-AV beams constructed by the main lobes of the sectorial sources are demonstrated by theoretical derivations, numerical simulations, and quality evaluations, while those created by the sidelobes are neglected to avoid the pressure fluctuations in the near field. Experimental measurements for AV beams of different orders coincide basically with the simulations, demonstrating that line-focused QB-AV beams can be generated along the beam axis across the pressure peak. With the increase of the topological charge, the peak pressure of the beam decreases accordingly with a reduced effective axial range. The favorable results prove that, as a special kind of diffraction sources, the adjustable QB-AV beams may enable more important biomedical applications where Bessel beams are necessary, especially for the line-focused manipulation of biological and drug particles.

Current Landscape of Sonodynamic Therapy for Treating Cancer

Simple Summary

Recently, ultrasound has advanced in its treatment opportunities. One example is sonodynamic therapy, a minimally invasive anti-cancer therapy involving a chemical sonosensitizer and focused ultrasound. The combination of the ultrasound and chemical sonosensitizer amplifies the drug’s ability to target cancer cells. Combining multiple chemical sonosensitizers with ultrasound can create a synergistic effect that could effectively disrupt tumorigenic growth, induce cell death, and elicit an immune response. This review provides an oversight of the application of this treatment to various types of cancer, including prostate cancer, glioma, and pancreatic ductal adenocarcinoma tumors.

Abstract

Recent advancements have tangibly changed the cancer treatment landscape. However, curative therapy for this dreadful disease remains an unmet need. Sonodynamic therapy (SDT) is a minimally invasive anti-cancer therapy involving a chemical sonosensitizer and focused ultrasound. A high-intensity focused ultrasound (HIFU) beam is used to destroy or denature targeted cancer tissues. Some SDTs are based on unfocused ultrasound (US). In some SDTs, HIFU is combined with a drug, known as a chemical sonosensitizer, to amplify the drug’s ability to damage cancer cells preferentially. The mechanism by which US interferes with cancer cell function is further amplified by applying acoustic sensitizers. Combining multiple chemical sonosensitizers with US creates a substantial synergistic effect that could effectively disrupt tumorigenic growth, induce cell death, and elicit an immune response. Therefore, the minimally invasive SDT treatment is currently attracting attention. It can be combined with targeted therapy (double-targeting cancer therapy) and immunotherapy in the future and is expected to be a boon for treating previously incurable cancers. In this paper, we will consider the current state of this therapy and discuss parts of our research.

Novel Therapeutic Method for Unresectable Pancreatic Cancer-The Impact of the Long-Term Research in Therapeutic Effect of High-Intensity Focused Ultrasound (HIFU) Therapy

High-intensity focused ultrasound (HIFU) is a novel advanced therapy for unresectable pancreatic cancer (PC). HIFU therapy with chemotherapy is being promoted as a novel method to control local advancement by tumor ablation. We evaluated the therapeutic effects of HIFU therapy in locally advanced and metastatic PC. PC patients were treated with HIFU as an optional local therapy and systemic chemotherapy. The FEP-BY02 (Yuande Bio-Medical Engineering) HIFU device was used under ultrasound guidance. Of 176 PC patients, 89 cases were Stage III and 87 were Stage IV. The rate of complete tumor ablation was 90.3%, while that of symptom relief was 66.7%. The effectiveness on the primary lesions were as follows: complete response (CR): n = 0, partial response (PR): n = 21, stable disease (SD): n = 106, and progressive disease (PD): n = 49; the primary disease control rate was 72.2%. Eight patients underwent surgery. The median survival time (MST) after diagnosis for HIFU with chemotherapy compared to chemotherapy alone (100 patients in our hospital) was 648 vs. 288 days (p < 0.001). Compared with chemotherapy alone, the combination of HIFU therapy and chemotherapy demonstrated significant prolongation of prognosis. This study suggests that HIFU therapy has the potential to be a novel combination therapy for unresectable PC.

The efficacy of a new high-intensity focused ultrasound therapy for metastatic pancreatic cancer

PURPOSE

To compare the survival benefit, pain control and safety of low-power cumulative and traditional high-intensity focused ultrasound (HIFU) for metastatic pancreatic cancer.

METHOD

We retrospectively analyzed 55 patients with metastatic pancreatic cancer who received HIFU treatment between January 2008 and April 2014 in our department. 23 patients received low-power cumulative HIFU treatment (L group), 32 received the traditional HIFU treatment (T group). Performance status, cancer-related pain and serum biochemistry results were assessed before and after treatment. All patients were followed up until death. The survival rate and adverse events of the two groups were compared.

RESULTS

The baseline characteristics of the two groups were generally well balanced (p > 0.05). The average KPS score after treatment was significantly improved in both groups compared with the baseline score. 36 patients exhibited tumor-related pain at baseline. The pain response rate was significantly higher in the L group (92.3%) than in the T group (52.2%) (p = 0.025). The median overall survival (OS) for the L group was 7.0 months, which was significantly longer than that of the T group (p = 0.000). The 3-month and 6-month survival rates were higher in the L group. The adverse events in both groups included abdominal pain, elevated C-reactive protein (CRP) and elevated amylase. The incidence was lower in the L group than in the T group.

CONCLUSION

Compared with traditional HIFU treatment, low-power cumulative HIFU treatment showed a significantly higher pain relief rate and survival benefit with a better safety profile in patients with metastatic pancreatic cancer.

Pulsed focused ultrasound can improve the anti-cancer effects of immune checkpoint inhibitors in murine pancreatic cancer

Pulsed high-intensity focused ultrasound (pHIFU) uses acoustic pressure to physically disrupt tumours. The aim of this study was to investigate whether pHIFU can be used in combination with immune checkpoint inhibitors (ICIs) to enhance survival of tumour-bearing animals. Murine orthotopic pancreatic KPC tumours were exposed both to a grid of pHIFU lesions (peak negative pressure = 17 MPa, frequency = 1.5 MHz, duty cycle = 1%, 1 pulse s-1, duration = 25 s) and to anti-CTLA-4/anti-PD-1 antibodies. Acoustic cavitation was detected using a weakly focused passive sensor. Tumour dimensions were measured with B-mode ultrasound before treatment and with callipers post-mortem. Immune cell subtypes were quantified with immunohistochemistry and flow cytometry. pHIFU treatment of pancreatic tumours resulted in detectable acoustic cavitation and increased infiltration of CD8+ T cells in the tumours of pHIFU and pHIFU + ICI-treated subjects compared with sham-exposed subjects. Survival of subjects treated with pHIFU + ICI was extended relative to both control untreated subjects and those treated with either pHIFU or ICI alone. Subjects treated with pHIFU + ICI had increased levels of CD8+IFNγ+ T cells, increased ratios of CD8+IFNγ+ to CD3+CD4+FoxP3+ and CD11b+Ly6G+ cells, and decreased CD11chigh cells in their tumours compared with controls. These results provide evidence that pHIFU combined with ICI may have potential for use in pancreatic cancer therapy.

Focused Ultrasound (FUS) for Chronic Pain Management: Approved and Potential Applications

Chronic pain is one of the leading causes of disability and disease burden worldwide, accounting for a prevalence between 6.9% and 10% in the general population. Pharmacotherapy alone results ineffective in about 70-60% of patients in terms of a satisfactory degree of pain relief. Focused ultrasound is a promising tool for chronic pain management, being approved for thalamotomy in chronic neuropathic pain and for bone metastases-related pain treatment. FUS is a noninvasive technique for neuromodulation and for tissue ablation that can be applied to several tissues. Transcranial FUS (tFUS) can lead to opposite biological effects, depending on stimulation parameters: from reversible neural activity facilitation or suppression (low-intensity, low-frequency ultrasound, LILFUS) to irreversible tissue ablation (high-intensity focused ultrasounds, HIFU). HIFU is approved for thalamotomy in neuropathic pain at the central nervous system level and for the treatment of facet joint osteoarthritis at the peripheral level. Potential applications include HIFU at the spinal cord level for selected cases of refractory chronic neuropathic pain, knee osteoarthritis, sacroiliac joint disease, intervertebral disc nucleolysis, phantom limb, and ablation of peripheral nerves. FUS at nonablative dosage, LILFUS, has potential reversible and tissue-selective effects. FUS applications at nonablative doses currently are at a research stage. The main potential applications include targeted drug and gene delivery through the Blood-Brain Barrier, assessment of pain thresholds and study of pain, and reversible peripheral nerve conduction block. The aim of the present review is to describe the approved and potential applications of the focused ultrasound technology in the field of chronic pain management.

Pancreas Cancer-Associated Pain Management

Pain is highly prevalent in patients with pancreas cancer and contributes to the morbidity of the disease. Pain may be due to pancreatic enzyme insufficiency, obstruction, and/or a direct mass effect on nerves in the celiac plexus. Proper supportive care to decrease pain is an important aspect of the overall management of these patients. There are limited data specific to the management of pain caused by pancreatic cancer. Here we review the literature and offer recommendations regarding multiple modalities available to treat pain in these patients. The dissemination and adoption of these best supportive care practices can improve quantity and quality of life for patients with pancreatic cancer. IMPLICATIONS FOR PRACTICE: Pain management is important to improve the quality of life and survival of a patient with cancer. The pathophysiology of pain in pancreas cancer is complex and multifactorial. Despite tumor response to chemotherapy, a sizeable percentage of patients are at risk for ongoing cancer-related pain and its comorbid consequences. Accordingly, the management of pain in patients with pancreas cancer can be challenging and often requires a multifaceted approach.

Low intensity focused ultrasound responsive microcapsules for non-ablative ultrafast intracellular release of small molecules

Focused ultrasound (FU) is in demand for clinical cancer therapy, but the possible thermal injury to the normal peripheral tissues limits the usage of the ablative FU for tumors with a large size; therefore research efforts have been made to minimize the possible side effects induced by the FU treatment. Non-ablative focused ultrasound assisted chemotherapy could open a new avenue for the development of cancer therapy technology. Here, low intensity focused ultrasound (LIFU) for controlled quick intracellular release of small molecules (Mw ≤ 1000 Da) without acute cell damage is demonstrated. The release is achieved by a composite poly(allylamine hydrochloride) (PAH)/poly-(sodium 4-styrenesulfonate) (PSS)/SiO2 microcapsules which are highly sensitive to LIFU and can be effectively broken by weak cavitation effects. Most PAH/PSS/SiO2 capsules in B50 rat neuronal cells can be ruptured and release rhodamine B (Rh-B) into the cytosol within only 30 s of 0.75 W cm-2 LIFU treatment, as demonstrated by the CLSM results. While the same LIFU treatment shows no obvious damage to cells, as proved by the live/dead experiment, showing that 90% of cells remain alive.

HSP90 inhibition acts synergistically with heat to induce a pro-immunogenic form of cell death in colon cancer cells

BACKGROUND

Sub-ablative heat induces pleiotropic biological effects in cancer cells, activating programmed cell death or survival processes. These processes decide the fate of the heated cell. This study investigates these and assesses whether heat, in combination with HSP90 inhibition, augments cell death and induces a pro-immune phenotype in these cells.

METHODS

HCT116 and HT29 cells were subjected to thermal doses (TID) of 60 and 120CEM43 using a PCR thermal cycler. HSP90 was inhibited with NVP-AUY922. Viability was assessed using the MTT assay. Cellular ATP and HSP70 release were assessed using ATP and Enzyme-linked Immunosorbent assays, respectively. Flow cytometry and immunoblotting were used to study the regulation of biomarkers associated with the heat shock response, the cell cycle, and immunogenic and programmed cell death.

RESULTS

Exposure of HCT116 and HT29 cells to TIDs of 60 and 120CEM43 decreased their viability. In addition, treatment with 120CEM43 increased intracellular HSP70 and the percentage of HCT116/HT29 cells in the G2/M cell cycle phase, ATP release and Calreticulin/HSP70/HSP90 exposure in the plasma membrane, while downregulating CD47 compared to sham-exposed cells. When combined with NVP-AUY922, treatment of HCT116/HT29 cells with 120CEM43 resulted in a synergistic decrease of cell viability associated with the induction of apoptosis. Also, the combined treatments increased Calreticulin exposure, CD47 downregulation, and HSP70 release compared to the sham-exposed cells.

CONCLUSION

Sub-ablative heating can act synergistically with the clinically relevant HSP90 inhibitor NVP-AUY922 to induce a pro-immunogenic form of cell death in colon cancer cells.

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.

In Vivo Non-Thermal, Selective Cancer Treatment With High-Frequency Medium-Intensity Focused Ultrasound

Focused ultrasound (FUS) has proven its efficacy in non-invasive, radiation-free cancer treatment. However, the commonly used low-frequency high-intensity focused ultrasound (HIFU) destroys both cancerous and healthy tissues non-specifically through extreme heat and inertial cavitation with low spatial resolution. To address this issue, we evaluate the therapeutic effects of pulsed (60 Hz pulse repetition frequency, 1.45 ms pulse width) high-frequency (20.7 MHz) medium-intensity (spatial-peak pulse-average intensity I_SPPA < 279.1 W/cm², spatial-peak temporal-average intensity I_SPTA < 24.3 W/cm²) focused ultrasound (pHFMIFU) for selective cancer treatment without thermal damage and with low risk of inertial cavitation (mechanical index < 0.66), in an in vivo subcutaneous B16F10 melanoma tumor growth model in mice. The pHFMIFU with 104 μm focal diameter is generated by a microfabricated self-focusing acoustic transducer (SFAT) with a Fresnel acoustic lens. A three-axis positioning system has been developed for automatic scanning of the transducer to cover a larger treatment volume, while a water-cooling system is custom-built for dissipating non-acoustic heat from the transducer surface. Initial testing revealed that pHFMIFU treatment can be applied to a living animal while maintaining skin temperature under 35.6 °C without damaging normal skin and tissue. After eleven days of treatment with pHFMIFU, the treated tumors were significantly smaller with large areas of necrosis and apoptosis in the treatment field compared to untreated controls. Potential mechanisms of this selective, non-thermal killing effect, as well as possible causes of and solutions to the variation in treatment results, have been analyzed and proposed. The pHFMIFU could potentially be used as a new therapeutic modality for safer cancer treatment especially in critical body regions, due to its cancer-specific effects and high spatial resolution.

Pain Control with Splanchnic Neurolysis in Pancreatic Cancer Patients Unresponsive to Celiac Plexus Neurolysis

BACKGROUND/AIMS

In most instances of abdominal pain associated with pancreatic cancer, pain may become refractory to increasing doses of narcotics. Celiac plexus neurolysis represents an option; however, altered celiac plexus anatomy may render this treatment infeasible or ineffective, where splanchnic nerve neurolysis may represent another option. This study aimed to investigate the outcomes of splanchnic neurolysis in pancreatic cancer patients not responsive to celiac plexus neurolysis.

PATIENTS AND METHODS

Among all 84 patients who underwent celiac plexus neurolysis for pancreatic cancer pain during the study period, 34 patients did not respond and underwent splanchnic nerve neurolysis under fluoroscopic guidance and thus included in this retrospective study. Stage IV, III, and II disease was present in 38.2%, 47.1%, and 14.7% of the patients. During the study, 88.2% were receiving chemotherapy, whereas none were on radiotherapy. Data for daily narcotic dose equivalents and Visual Analogue Scale (VAS) scores during outpatient visits at baseline, 2 weeks, 2 months, and 3 months were extracted.

RESULTS

Pain response rates were 76.5%, 84.4%, and 71.0%, at 2 weeks, 2 months, and 3 months, respectively. A significant and dramatic reduction was seen in VAS scores at 2 weeks (2.8±1.2 versus 6.3±1.1, p<0.001), and this significant decline was maintained for 3 months. Similarly, a significant and dramatic reduction was seen in daily narcotic need at 2 weeks (20.8±32.9 versus 93.4±86.2 mg, p<0.001), which was also maintained during the 3-month follow-up. The procedure was generally well tolerated.

CONCLUSION

Findings of this study suggest that splanchnic neurolysis represents a durable and effective option for pain control in pancreatic cancer patients in whom the neurolysis of the celiac plexus is ineffective. However, these conclusions refer to only preliminary single-center results in a selected patient group; thus, further large studies are warranted.

A computational study of combination HIFU-chemotherapy as a potential means of overcoming cancer drug resistance

The application of local hyperthermia, particularly in conjunction with other treatment strategies (like chemotherapy and radiotherapy) has been known to be a useful means of enhancing tumor treatment outcomes. However, to our knowledge, there has been no mathematical model designed to capture the impact of the combination of hyperthermia and chemotherapies on tumor growth and control. In this study, we propose a nonlinear Partial Differential Equation (PDE) model which describes the tumor response to chemotherapy, and use the model to study the effects of hyperthermia on the response of prototypical tumor to the generic chemotherapeutic agent. Ultrasound energy is delivered to the tumor through High Intensity Focused Ultrasound (HIFU), as a noninvasive technique to elevate the tumor temperature in a controlled manner. The proposed tumor growth model is coupled with the nonlinear density dependent Westervelt and Penne's bio-heat equations, used to calculate the net delivered energy and temperature of the tumor and its surrounding normal tissue. The tumor is assumed to be composed of two species: drug-sensitive and drug-resistant. The central assumption underlying our model is that the drug-resistant species is converted to a drug-sensitive type when the tumor temperature is elevated above a certain threshold temperature. The "in silico" results obtained, confirm that hyperthermia can result in less aggressive tumor development and emphasize the importance of designing an optimized thermal dose strategy. Furthermore, our results suggest that increasing the length of the on/off cycle of the transducer is an efficient approach to treatment scheduling in the sense of optimizing tumor eradication.

Effects of high-intensity focused ultrasound treatment on peripancreatic arterial and venous blood vessels in pancreatic cancer

The present study aimed to evaluate the safety of high-intensity focused ultrasound (HIFU) treatment on peripancreatic arterial and venous blood vessels in patients with pancreatic cancer. This trial included 15 patients with pancreatic cancer (9 females and 6 males; age, 39-81 years; median age, 62 years). All patients underwent preoperative computed tomography (CT) or magnetic resonance imaging (MRI) and color Doppler flow imaging (CDFI) to assess the vascular hemodynamics of peripancreatic arterial and venous blood vessels pre-treatment. These patients were re-examined within 1 week post-HIFU treatment. Then, vascular adverse events were observed and followed up clinically. Prior to HIFU treatment, vessel involvement was recorded in 13 patients, including tumor lesions invading 19 veins and 14 arteries, which refers to the growth of pancreatic tumor lesions surrounding blood vessels, or tumor growth into blood vessels. In addition, 9 veins and 13 arteries were <1 cm from the lesions. The hemodynamic parameters of peripancreatic vessels were measured using CDFI, including mean blood flow velocity, peak systolic blood flow velocity, vascular resistance index, vascular pulsatility index, vascular diameter, vascular blood flow and other indicators, to assess vascular perfusion in CT/MRI. There were no significant differences in preoperative and postoperative hemodynamic data (P>0.05). Overall, HIFU demonstrated no negative effects on peripancreatic arterial and venous blood vessels in patients with pancreatic cancer, even with tumor lesions wrapped in blood vessels. In addition, no complications of vascular stenosis and vascular adverse events were observed in the present study.

A Retrospective Case Series Of High-Intensity Focused Ultrasound (HIFU) In Combination With Gemcitabine And Oxaliplatin (Gemox) On Treating Elderly Middle And Advanced Pancreatic Cancer

Purpose

This retrospective study was conducted to evaluate the safety and efficacy of high-intensity focused ultrasound (HIFU) ablation combined with Gemcitabine and Oxaliplatin (Gemox) for the treatment of middle and advanced pancreatic cancer in elderly patients.

Methods

Forty-seven patients with pancreatic cancer treated with HIFU and Gemox were evaluated for inclusion, and 38 cases were finally included. The primary endpoint was safety. Secondary endpoints included the response rate, the clinical benefit response (CBR), overall survival (OS), progression-free survival (PFS).

Results

After combination therapy of HIFU and Gemox, severe complications were rarely reported, and no treatment-related death occurred. The rate of three or four-degree myelosuppression was low, and no obvious impairment of hepatorenal function was observed. Pancreatitis and gastrointestinal injury did not occurred. The disease control rate (DCR) was estimated to be 76.3%, including complete remission (CR), partial remission (PR), stable disease (SD) in 1, 6, 22 cases, respectively. And the objective response rate (ORR) was 18.4%. The clinical benefit rate (CBR) was 68.4%, with the pain significantly relieved (P<0.01). The serum level of CA19-9 showed significant changes after HIFU treatment. The median overall survival (OS) was 12.5 months, with a 6-month and 12-month OS rate of 82.13% and 59.34%, respectively. Stratified analyses did not reveal any significant difference between patients in different stages.

Conclusion

Elderly patients (≥ 60 years old) with pancreatic cancer would experience tolerable toxicity and obtain good clinical benefits from the combination therapy of HIFU ablation and Gemox.

High-resolution intravascular MRI-guided perivascular ultrasound ablation

PURPOSE

To develop and test in animal studies ex vivo and in vivo, an intravascular (IV) MRI-guided high-intensity focused ultrasound (HIFU) ablation method for targeting perivascular pathology with minimal injury to the vessel wall.

METHODS

IV-MRI antennas were combined with 2- to 4-mm diameter water-cooled IV-ultrasound ablation catheters for IV-MRI on a 3T clinical MRI scanner. A software interface was developed for monitoring thermal dose with real-time MRI thermometry, and an MRI-guided ablation protocol developed by repeat testing on muscle and liver tissue ex vivo. MRI thermal dose was measured as cumulative equivalent minutes at 43°C (CEM₄₃ ). The IV-MRI IV-HIFU protocol was then tested by targeting perivascular ablations from the inferior vena cava of 2 pigs in vivo. Thermal dose and lesions were compared by gross and histological examination.

RESULTS

Ex vivo experiments yielded a 6-min ablation protocol with the IV-ultrasound catheter coolant at 3-4°C, a 30 mL/min flow rate, and 7 W ablation power. In 8 experiments, 5- to 10-mm thick thermal lesions of area 0.5-2 cm² were produced that spared 1- to 2-mm margins of tissue abutting the catheters. The radial depths, areas, and preserved margins of ablation lesions measured from gross histology were highly correlated (r ≥ 0.79) with those measured from the CEM₄₃ = 340 necrosis threshold determined by MRI thermometry. The psoas muscle was successfully targeted in the 2 live pigs, with the resulting ablations controlled under IV-MRI guidance.

CONCLUSION

IV-MRI-guided, IV-HIFU has potential as a precision treatment option that could preserve critical blood vessel wall during ablation of nonresectable perivascular tumors or other pathologies.

Effective high intensity focused ultrasound treatment in recurrent aggressive breast fibromatosis: a case report

Aggressive breast fibromatosis (referred to as a desmoid tumor) is a rare, locally invasive, non-metastasizing tumor with high recurrence rate. The therapeutic modalities range from surgery and radiotherapy to medical treatments. However, the optimal treatment is controversial, especially in a situation of repeated recurrence. Here, we present a case of a patient with aggressive breast fibromatosis with multiple recurrence after surgeries, who underwent high intensity focused ultrasound (HIFU) treatment effectively without side effects. To our knowledge, this is the first reported case of HIFU treatment in aggressive breast fibromatosis, which indicates that HIFU might be a novel, promising modality for this rare disease.

HIFU is safe, effective, and feasible in pancreatic cancer patients: a monocentric retrospective study among 523 patients

Purpose

This study aimed to evaluate the clinical value of high-intensity focused ultrasound (HIFU) combined with gemcitabine (GEM) in treating unresectable pancreatic ductal adenocarcinoma (PDAC).

Patients and methods

A total of 523 unresectable PDAC patients were recruited from December 30, 2007 to January 30, 2015 at Fudan University Shanghai Cancer Center. Among them, 347 received HIFU combined with GEM (with regional intra-arterial chemotherapy [RIAC] or with systemic chemotherapy) and the remaining patients received GEM only. Postoperative complications were observed, and overall survival was recorded.

Results

The median overall survival of patients who received HIFU combined with GEM vs GEM alone was 7.4 vs 6.0 months (P=0.002); the 6-month, 10-month, 1-year, and 2-year survival rates for patients in these two groups were 66.3% vs 47.5% (P<0.0001), 31.12% vs 15.9% (P<0.0001), 21.32% vs 13.64% (P=0.033), and 2.89% vs 2.27% (P=0.78), respectively. In the combined therapy group, the most obvious survival benefits were obtained among patients who received HIFU plus RIAC and systemic chemotherapy (used in the intervals between RIAC treatments). There were no severe complications in patients undergoing HIFU treatment.

Conclusion

We demonstrated the survival benefit of HIFU among PDAC patients treated with GEM. The benefit was most obvious in PDAC patients treated with HIFU plus RIAC and systemic chemotherapy.

Mesoporous Silica Nanoparticles for Dual-Mode Chemo-Sonodynamic Therapy by Low-Energy Ultrasound

Low-energy ultrasound (LEUS), exhibiting obvious advantages as a safe therapeutic strategy, would be promising for cancer therapy. We had synthesized a LEUS-responsive targeted drug delivery system based on functional mesoporous silica nanoparticle for cancer therapy. Paclitaxel (PTX) was loaded in mesoporous silica nanoparticles with a hydrophobic internal channel, and folic acid (FA) functionalized β-Cyclodextrin (β-CD) was capped on the surface of the nanoparticles (DESN), which acted as a cancer-targeting moiety and solubilizer. The existence of a hydrophobic internal channel in the DESN was beneficial to the storage of hydrophobic PTX, along with the enhancement of the cavitation effect produced by mild low-energy ultrasound (LEUS, ≤1.0 W/cm², 1 MHz). The DESN showed significantly enhanced cavitation effect, selective targeting, and achieved a rapid drug release under mild LEUS. To investigate the in vivo antitumor efficacy of the DESN upon LEUS irradiation, we established a 4T1 mammary tumor model. The DESN were confirmed to be of great biodegradability/biocompatibility. The tumor growth was significantly inhibited when the mice were treated with DESN (10 mg/kg) + LEUS with the relative tumor volume reduced to 4.72 ± 0.70 compared with the control group (V/V₀ = 17.12 ± 2.75). The DESN with LEUS represented excellent inhibiting effect on tumor cell in vivo. This work demonstrated that DESN mediating dual mode chemo-sonodynamic therapy could be triggered by extracorporeal remote control, may suggest a promising clinical application in cancer therapy.

Response of patients with locally advanced pancreatic adenocarcinoma to high-intensity focused ultrasound treatment: a single-center, prospective, case series in China

Purpose

Patients with unresectable locally advanced pancreatic cancer (LAPC) are still in dire need of effective therapies. We performed this cohort study in order to assess the efficacy and safety of high-intensity focused ultrasound (HIFU) ablation in treating patients with unresectable LAPC.

Patients and methods

Eighty-seven cases with unresectable LAPC from January 2014 to December 2016 were finally recruited according to the inclusion criteria. The primary end point of our study was OS of all the cases, and the secondary end points included 6-month and 12-month survival rate, tumor response rate, carbohydrate antigen (CA) 19-9 response rate, VAS, quality of life, and safety.

Results

All the 87 patients received HIFU ablation successfully, and were included in the efficacy and safety analysis. With a median follow-up of 16 months, median OS was estimated to be 12.2 months, with 95 % CI of 11.1–12.7 months. The 6-month and 12-month survival rates were 94.25% (95% CI =86.74–97.57) and 50.85% (95% CI =38.17–62.21), respectively. Multivariate analysis revealed that patients with VAS <4, Karnofsky performance status ≥80, and tumor size <3 cm have a significant improvement in their OS (adjusted HR [aHR] =0.26 [95% CI =0.12–0.57], P=0.001; aHR =0.34 [95% CI =0.17–0.68], P=0.02; and aHR =0.39 [95% CI =0.20–0.78], P=0.007; respectively). Tumor responses were observed in 32 (36.8%) of 87 patients and CA 19-9 response rate was 56.2%. Global health status, physical function, emotional function, and cognitive function of patients were significantly improved after HIFU treatment, and symptoms of fatigue and pain were significantly reduced. A total of 28.7% (25/87) of patients reported adverse events (AEs), mainly including fatigue (14/87), abdominal pain (7/87), fever (7/87), nausea (5/87), and rash (4/87). No severe AEs and HIFU-related deaths were reported.

Conclusion

HIFU ablation might be a potentially effective and safe therapeutic option for the patients with unresectable LAPC.

A portable high-intensity focused ultrasound system for the pancreas with 3D electronic steering: a preclinical study in a swine model

PURPOSE

The aim of this animal study was to evaluate the safety and feasibility of a portable, ultrasonography-guided, high-intensity focused ultrasound (USg-HIFU) system to treat the pancreas.

METHODS

Eight swine were included. Using a portable HIFU device (ALPIUS 900, Alpinion Medical Systems), ablations were performed on the pancreas in vivo. Different acoustic intensities were applied (1.7 kW/cm2 or 1.5 kW/cm2 , n=2 [group A for a pilot study]; 1.5 kW/ cm2 , n=3 [group B]; and 1.2 kW/cm2 , n=3 [group C]). Magnetic resonance imaging (MRI) was performed immediately (group A) or 7 days (groups B and C) after HIFU treatment. In groups B and C, serum amylase and lipase levels were measured on days 0 and 7, and performance status was observed every day. Necropsy was performed on days 0 (group A) or 7 (groups B and C) to assess the presence of unintended injuries and to obtain pancreatic and peripancreatic tissue for histological analysis.

RESULTS

Ablation was noted in the pancreas in all swine on MRI, and all pathologic specimens showed coagulation necrosis in the treated area. The mean ablation areas on MRI were 85.3±38.1 mm2, 90.7±21.2 mm2, and 54.4±30.6 mm2 in groups A, B, and C, respectively (P>0.05). No animals showed evidence of complications, except for one case of a pseudocyst in group B.

CONCLUSION

This study showed that pancreas ablation using a portable USg-HIFU system may be safe and feasible, and that coagulation necrosis of the pancreas was successfully achieved with a range of acoustic intensities.

Focused ultrasound for immuno-adjuvant treatment of pancreatic cancer: An emerging clinical paradigm in the era of personalized oncotherapy

Current clinical treatment regimens, including many emergent immune strategies (e.g., checkpoint inhibitors) have done little to affect the devastating course of pancreatic ductal adenocarcinoma (PDA). Clinical trials for PDA often employ multi-modal treatment, and have started to incorporate stromal-targeted therapies, which have shown promising results in early reports. Focused ultrasound (FUS) is one such therapy that is uniquely equipped to address local and systemic limitations of conventional cancer therapies as well as emergent immune therapies for PDA. FUS methods can non-invasively generate mechanical and/or thermal effects that capitalize on the unique oncogenomic/proteomic signature of a tumor. Potential benefits of FUS therapy for PDA include: (1) emulsification of targeted tumor into undenatured antigens in situ, increasing dendritic cell maturation, and increasing intra-tumoral CD8+/ T regulatory cell ratio and CD8+ T cell activity; (2) reduction in intra-tumoral hypoxic stress; (3) modulation of tumor cell membrane protein localization to enhance immunogenicity; (4) modulation of the local cytokine milieu toward a Th1-type inflammatory profile; (5) up-regulation of local chemoattractants; (6) remodeling the tumor stroma; (7) localized delivery of exogenously packaged immune-stimulating antigens, genes and therapeutic drugs. While not all of these results have been studied in experimental PDA models to date, the principles garnered from other solid tumor and disease models have direct relevance to the design of optimal FUS protocols for PDA. In this review, we address the pertinent limitations in current and emergent immune therapies that can be improved with FUS therapy for PDA.

The efficacy of a new high intensity focused ultrasound therapy for locally advanced pancreatic cancer

PURPOSE

To compare the survival benefit and safety of the low power cumulative and traditional high intensity focused ultrasound (HIFU) for locally advanced pancreatic cancer.

METHOD

We retrospectively analyzed 38 patients with locally advanced, inoperable, stage III pancreatic patients received HIFU treatment between January 2008 and April 2014 in the Department of Surgery, the Second Affiliated Hospital, Zhejiang University, School of Medicine. 11 of them received the low power cumulative HIFU treatment, while other 27 received the traditional HIFU treatment. The HIFU device used was the FEP-BY02 (Yuande Biomedical Engineering Co. Ltd, Beijing, China). Serum biochemistry and adverse events were assessed before and after treatment. All the patients were followed up until death. The survival rate and adverse events of two groups were compared.

RESULTS

In 38 patients, the baseline characteristics including gender, age, Karnofsky performance status (KPS) score, tumor location of two groups were generally well balanced (P > 0.05). The median overall survival (OS) for low power cumulative HIFU group was 10.3 months (95% CI, 6.3-14.3 months), which is significantly longer than traditional HIFU group with 6.0 months (95% CI, 5.2-6.8 months) (P = 0.018). In low power cumulative HIFU group, the 6-month and 12-month survival rates were higher than traditional group, 100% v.s 44.4%, 11.1% v.s 36.4%, respectively. The adverse events in both groups include abdominal pain, fever, C-reactive protein (CRP) elevated. The incidence was lower in low power cumulative HIFU group, however, without statistical significance.

CONCLUSION

The low power cumulative HIFU treatment showed a statistical significance in survival benefit with better safety profile compared to the traditional HIFU treatment in patients with locally advanced pancreatic cancer.

High-intensity focused ultrasound-triggered nanoscale bubble-generating liposomes for efficient and safe tumor ablation under photoacoustic imaging monitoring

High-intensity focused ultrasound (HIFU) is widely applied to tumors in clinical practice due to its minimally invasive approach. However, several issues lower therapeutic efficiency in some cases. Many synergists such as microbubbles and perfluorocarbon nanoparticles have recently been used to improve HIFU treatment efficiency, but none were determined to be effective and safe in vivo. In this study, nanoscale bubble-generating liposomes (liposomes containing ammonium bicarbonate [Lip-ABC]) were prepared by film hydration followed by sequential extrusion. Their stable nanoscale particle diameter was confirmed, and their bubble-generating capacity after HIFU triggering was demonstrated with ultrasound imaging. Lip-ABC had good stability in vivo and accumulated in the tumor interstitial space based on the enhanced permeability and retention effect evaluated by photoacoustic imaging. When used to synergize HIFU ablation to bovine liver in vitro and implanted breast tumors of BALB/c nude mice, Lip-ABC outperformed the control. Importantly, all mice survived HIFU treatment, suggesting that Lip-ABC is a safe HIFU synergist.

Fluid filling of the digestive tract for improved proton resonance frequency shift-based MR thermometry in the pancreas

PURPOSE

To demonstrate that fluid filling of the digestive tract improves the performance of respiratory motion-compensated proton resonance frequency shift (PRFS)-based magnetic resonance (MR) thermometry in the pancreas.

MATERIALS AND METHODS

In seven volunteers (without heating), we evaluated PRFS thermometry in the pancreas with and without filling of the surrounding digestive tract. All data acquisition was performed at 1.5T, then all datasets were analyzed and compared with three different PRFS respiratory motion-compensated thermometry methods: gating, multibaseline, and referenceless. The temperature precision of the different methods was evaluated by assessing temperature standard deviation over time, while a simulation experiment was used to study the accuracy of the methods.

RESULTS

Without fluid intake, errors in temperature precision in the pancreas up to 10°C were observed for all evaluated methods. After liquid intake, temperature precision improved to median values between 1.8 and 2.9°C. The simulations showed that gating had the lowest accuracy, with errors up to 7°C. Multibaseline and referenceless thermometry performed better, with a median error in the pancreas between -3 and +3°C after fluid intake, for all volunteers.

CONCLUSION

Preparation of the digestive tract near the pancreas by filling it with fluid improved MR thermometry precision and accuracy for all common respiratory motion-compensated methods evaluated. These improvements are attributed to reducing field inhomogeneity in the pancreas.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:692-701.

A Strategy for Precise Treatment of Cardiac Malignant Neoplasms

The prevalence of cardiac malignant neoplasms in the general population has been shown to be significant higher than what was previously estimated, yet their treatment has remained difficult and effective therapies are lacking. In the current study, we developed a novel thermotherapy in which PEG-functionalized carbon nanotubes were injected into the tumor regions to assist in the targeted delivery of infrared radiation energy with minimal hyperthermic damage to the surrounding normal tissues. In a mouse model of cardiac malignant neoplasms, the injected carbon nanotubes could rapidly induce coagulative necrosis of tumor tissues when exposed to infrared irradiation. In accordance, the treatment was also found to result in a restoration of heart functions and a concomitant increase of survival rate in mice. Taken together, our carbon nanotube-based thermotherapy successfully addressed the difficulty facing conventional laser ablation methods with regard to off-target thermal injury, and could pave the way for the development of more effective therapies against cardiac malignant neoplasms.

A meta-analysis of palliative treatment of pancreatic cancer with high intensity focused ultrasound

BACKGROUND

Pancreatic adenocarcinoma is currently the fourth-leading cause of cancer-related death. Up to 60-90% of patients with advanced disease suffer cancer-related pain, severely impacting their quality of life. Current management involves primarily pharmacotherapy with opioid narcotics and celiac plexus neurolysis; unfortunately, both approaches offer transient relief and cause undesired side-effects. High intensity focused ultrasound (HIFU) is a non-invasive thermal ablation technique that has been used to treat pancreatic cancer. This meta-analysis aims to evaluate the role of HIFU in pain palliation of advanced unresectable pancreatic adenocarcinoma.

METHODS

An electronic search was performed in PubMed Medline database up to the end of July 2016, for unresectable pancreatic cancer pain palliation with HIFU. Pertinent studies were identified through the PubMed search engine using the following keywords: HIFU, pancreas, pancreatic cancer, pain and palliation. Additional studies were included after manual search of the selected bibliographies. Pain palliation results reported in each study were analyzed using a logit-transformed random-effects model using the inverse variance method, with the DerSimonian-Laird estimator for τ2, and Cochran's Q test for heterogeneity among studies. The I2 was calculated to assess the percentage of the total variability in the different effect size estimates that can be attributed to heterogeneity among the true effects. A rank correlation test of funnel plot asymmetry was done to assess possible publication bias.

RESULTS

The meta-analysis includes a total number of 23 studies with 865 patients, 729 with pancreatic cancer. The population enrolled ranges from 3 patients in the smallest series, up to 61 in the largest study. τ2 (variance among studies) was 0.195, and I2 (percentage of variation among studies) was 40% (95% CI: 1-64%); the Q test p-value was 0.026, indicating significant heterogeneity among studies. Among 639 patients treated with HIFU, 567 complained of pancreatic pain before the treatment and 459 patients experienced partial or complete pain relief after treatment. The random effects estimate of the proportion of patients with pain reduction was 0.81 (95% CI: 0.76-86).

CONCLUSIONS

HIFU appears to be an effective tool for pain palliation in advanced pancreatic cancer. Studies assessing treatment in patients with pancreatic adenocarcinoma are limited by factors such as small sample sizes and heterogeneity in clinical definitions and assessments. Prospective randomized and standardized studies are necessary to confirm the effectiveness of HIFU in relieving pain, and to evaluate for any potential impact on tumor control and patient survival.

Endoluminal ultrasound applicators for MR-guided thermal ablation of pancreatic tumors: Preliminary design and evaluation in a porcine pancreas model

PURPOSE

Endoluminal ultrasound may serve as a minimally invasive option for delivering thermal ablation to pancreatic tumors adjacent to the stomach or duodenum. The objective of this study was to explore the basic feasibility of this treatment strategy through the design, characterization, and evaluation of proof-of-concept endoluminal ultrasound applicators capable of placement in the gastrointestinal (GI) lumen for volumetric pancreas ablation under MR guidance.

METHODS

Two variants of the endoluminal applicator, each containing a distinct array of two independently powered transducers (10 × 10 mm 3.2 MHz planar; or 8 × 10 × 20 mm radius of curvature 3.3 MHz curvilinear geometries) at the distal end of a meter long flexible catheter assembly, were designed and fabricated. Transducers and circulatory water flow for acoustic coupling and luminal cooling were contained by a low-profile polyester balloon covering the transducer assembly fixture. Each applicator incorporated miniature spiral MR coils and mechanical features (guiding tips and hinges) to facilitate tracking and insertion through the GI tract under MRI guidance. Acoustic characterization of each device was performed using radiation force balance and hydrophone measurements. Device delivery into the upper GI tract, adjacent to the pancreas, and heating characteristics for treatment of pancreatic tissue were evaluated in MR-guided ex vivo and in vivo porcine experiments. MR guidance was utilized for anatomical target identification, tracking/positioning of the applicator, and MR temperature imaging (MRTI) for PRF-based multislice thermometry, implemented in the real-time RTHawk software environment.

RESULTS

Force balance and hydrophone measurements indicated efficiencies of 48.8% and 47.8% and -3 dB intensity beam-widths of 3.2 and 1.2 mm for the planar and curvilinear transducers, respectively. Ex vivo studies on whole-porcine carcasses revealed capabilities of producing ablative temperature rise (ΔT > 15 °C) contours in pancreatic tissue 4-40 mm long and 4-28 mm wide for the planar transducer applicator (1-13 min sonication duration, ∼4 W/cm(2) applied acoustic intensity). Curvilinear transducers produced more selective heating, with a narrower ΔT > 15 °C contour length and width of up to 1-24 mm and 2-7 mm, respectively (1-7 min sonication duration, ∼4 W/cm(2) applied acoustic intensity). Active tracking of the miniature spiral coils was achieved using a Hadamard encoding tracking sequence, enabling real-time determination of each coil's coordinates and automated prescription of imaging planes for thermometry. In vivo MRTI-guided heating trials in three pigs demonstrated capability of ∼20 °C temperature elevation in pancreatic tissue at 2 cm depths from the applicator, with 5-7 W/cm(2) applied intensity and 6-16 min sonication duration. Dimensions of thermal lesions in the pancreas ranged from 12 to 28 mm, 3 to 10 mm, and 5 to 10 mm in length, width, and depth, respectively, as verified through histological analysis of tissue sections. Multiple-baseline reconstruction and respiratory-gated acquisition were demonstrated to be effective strategies in suppressing motion artifacts for clear evolution of temperature profiles during MRTI in the in vivo studies.

CONCLUSIONS

This study demonstrates the technical feasibility of generating volumetric ablation in pancreatic tissue using endoluminal ultrasound applicators positioned in the stomach lumen. MR guidance facilitates target identification, device tracking/positioning, and treatment monitoring through real-time multislice PRF-based thermometry.

Using High-Intensity Focused Ultrasound as a Means to Provide Targeted Drug Delivery

High-intensity focused ultrasound (HIFU)–mediated drug delivery is a relatively novel technique used to deliver drugs to a targeted location in the body. High-intensity focused ultrasound–mediated drug delivery has a broad range of applications, such as tumor therapy, treating central nervous diseases, transsclera drug delivery, and cardiovascular treatments. Targeted treatments prove to be advantageous to systemic treatments due to the reduction in the associated side effects. Thus, this literature review focuses on the various applications of HIFU-mediated drug delivery as well as the mechanism involved. This article is intended to supply the reader with a detailed description of how this technique can be used as well as describe its potential to surpass other treatment methods. Further discussion on the efficiency, limitations, and future of HIFU-mediated drug delivery is addressed. Furthermore, the gaps in the published literature, relative to this topic, are discussed. Ultimately, HIFU-mediated drug delivery is a developing technique that could provide patients with exciting treatment options.

High intensity focused ultrasound (HIFU) applied to hepato-bilio-pancreatic and the digestive system-current state of the art and future perspectives

BACKGROUND

High intensity focused ultrasound (HIFU) is emerging as a valid minimally-invasive image-guided treatment of malignancies. We aimed to review to current state of the art of HIFU therapy applied to the digestive system and discuss some promising avenues of the technology.

METHODS

Pertinent studies were identified through PubMed and Embase search engines using the following keywords, combined in different ways: HIFU, esophagus, stomach, liver, pancreas, gallbladder, colon, rectum, and cancer. Experimental proof of the concept of endoluminal HIFU mucosa/submucosa ablation using a custom-made transducer has been obtained in vivo in the porcine model.

RESULTS

Forty-four studies reported on the clinical use of HIFU to treat liver lesions, while 19 series were found on HIFU treatment of pancreatic cancers and four studies included patients suffering from both liver and pancreatic cancers, reporting on a total of 1,682 and 823 cases for liver and pancreas, respectively. Only very limited comparative prospective studies have been reported.

CONCLUSIONS

Digestive system clinical applications of HIFU are limited to pancreatic and liver cancer. It is safe and well tolerated. The exact place in the hepatocellular carcinoma (HCC) management algorithm remains to be defined. HIFU seems to add clear survival advantages over trans arterial chemo embolization (TACE) alone and similar results when compared to radio frequency (RF). For pancreatic cancer, HIFU achieves consistent cancer-related pain relief. Further research is warranted to improve targeting accuracy and efficacy monitoring. Furthermore, additional work is required to transfer this technology on appealing treatments such as endoscopic HIFU-based therapies.

The Asian Grocery Store-Based Cancer Education Program: Creating New Education Modules

Operating since 1994, the UCSD Moores Cancer Center's Asian Grocery Store-Based Cancer Education Program (the Program) is a proven and sustainable strategy for disseminating cancer and poison control information to Asian and Pacific Islander (API) communities. This paper describes the process taken to identify health topics that can be readily addressed within the Program's infrastructure and reports results of the pilot testing of the educational module that was developed by following that process. The development of each new module is guided by the Health Belief Model and the Tipping Point Model. The process starts with the selection of a health topic demonstrating pressing need and treatment options in the API community. Then, using the Pareto principle, reasonably modifiable risk factors are chosen to be addressed in the module. "Sticky messaging" for the modifiable risk factors is developed to package the health information as memorable and transmissible calls-to-action. Finally, grocery store outreaches were used to pilot test the new module to assess its effectiveness at facilitating health care information to API community members. By adhering to the steps described in this paper, the authors were able to: (1) select liver cancer as a pressing API health issue that could be positively impacted by the Program; (2) identify reasonably modifiable risk factors for the chosen health issue; (3) generate compelling call-to-action messages to decrease risk of exposure; and (4) demonstrate the cultural and linguistic alignment of the liver cancer control module. The development and testing of new health education modules follow a methodical process guided by scientific principles. Understanding and employing the elements of an existing evidence-based and sustainable health education program can increase the likelihood of success in addressing the health needs of the API community.

Clinical applications of low-intensity pulsed ultrasound and its potential role in urology

Low-intensity pulsed ultrasound (LIPUS) is a form of ultrasound that delivered at a much lower intensity (<3 W/cm²) than traditional ultrasound energy and output in the mode of pulse wave, and it is typically used for therapeutic purpose in rehabilitation medicine. LIPUS has minimal thermal effects due to its low intensity and pulsed output mode, and its non-thermal effects which is normally claimed to induce therapeutic changes in tissues attract most researchers’ attentions. LIPUS have been demonstrated to have a rage of biological effects on tissues, including promoting bone-fracture healing, accelerating soft-tissue regeneration, inhibiting inflammatory responses and so on. Recent studies showed that biological effects of LIPUS in healing morbid body tissues may be mainly associated with the upregulation of cell proliferation through activation of integrin receptors and Rho/ROCK/Src/ERK signaling pathway, and with promoting multilineage differentiation of mesenchyme stem/progenitor cell lines through ROCK-Cot/Tpl2-MEK-ERK signaling pathway. Hopefully, LIPUS may become an effective clinical procedure for the treatment of urological diseases, such as chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), erectile dysfunction (ED), and stress urinary incontinence (SUI) in the field of urology. It still needs an intense effort for basic-science and clinical investigators to explore the biomedical applications of ultrasound.

The Effect of Radiotherapy on Ultrasound-Guided Fine Needle Aspiration Biopsy and the Ultrasound Characteristics of Neck Lymph Nodes in Oral Cancer Patients after Primary Treatment

Objectives

To investigate the effect of radiotherapy (RT) on ultrasound-guided fine needle aspiration (USgFNA) and sonographic characteristics in the assessment of cervical lymph nodes (LNs) in oral squamous cell carcinoma (OSCC) patients after primary treatment.

Materials and Methods

88 treated OSCC patients underwent 111 USgFNAs of the neck LNs after US evaluation. Among them, 48 USgFNAs were performed on 40 patients following RT and 63 USgFNAs on 48 patients without previous RT. The results of USgFNA and the US characteristics were compared between these two groups.

Results

USgFNA had a sensitivity of 88.0%, specificity of 91.4%, positive predictive value (PPV) of 88.0%, negative predictive value (NPV) of 91.4% and accuracy of 90.0% in patients without previous RT, and a sensitivity of 97.1%, specificity of 83.3%, PPV of 94.3%, NPV of 90.9% and accuracy of 93.5% in those with previous neck RT. The ranges of the short-axis and long-axis length were 13.3 ± 8.0 mm (mean ± SD) versus 17.8 ± 9.1 mm, and 18.6 ± 9.0 mm versus 24.4 ± 10.9 mm for recurrent LNs from patients with, versus without, previous RT (both ps < 0.05), respectively. 76.5% (26/34) of the recurrent nodes after RT and 48% (12/25) of the recurrent nodes without previous RT exhibited an irregular margin (p < 0.05). Additionally, irradiated recurrent LNs had a significantly decreased percentage of discernable calcification compared with non-irradiated recurrent nodes (48% versus 20.6%, p < 0.05).

Conclusions

RT had influence on sonographic characteristics but no influence on USgFNA in diagnosing recurrent LNs in treated OSCC patients.

The combination therapy of high-intensity focused ultrasound with radiotherapy in locally advanced pancreatic carcinoma

BACKGROUND

The aim of the present study is to evaluate the effectiveness of the combined application of high-intensity focused ultrasound (HIFU) and radiotherapy in the treatment of locally advanced pancreatic carcinoma (LAPC).

METHODS

A total number of sixteen patients with LAPC started treatment beginning with HIFU and radiotherapy 1 week after the HIFU treatment. Evaluation of the effectiveness of treatment was performed using main clinical symptoms, serum levels of CA-19-9, Response Evaluation Criteria in Solid Tumors (RECIST) guidelines, and the Kaplan-Meier method for estimating median overall survival (OS). The occurrence of adverse reactions was recorded.

RESULTS

The main clinical symptoms including abdominal pain and lower back pain were alleviated, and the mean visual analog scale (VAS) pain score declined from 5.1 points to just 3.3 points immediately after the HIFU treatment. The median pain relief time was 5.6 months after radiotherapy, serum CA-19-9 levels began to decrease significantly 1 week after the HIFU treatment, from 102.1 to 60.8 U/ml, and the median continuous decline time was 4.3 months after radiotherapy. Partial response (PR) was observed in seven of sixteen patients, with stable disease (SD) in four patients, and progressive disease (PD) in the remaining five patients at 6 months after radiotherapy. Serum levels of amylopsin and lipase were not elevated to abnormal levels. The median OS was 14 months. No serious adverse reactions occurred.

CONCLUSIONS

Treatment with both HIFU and radiotherapy can quickly improve symptoms and the quality of life and prolong survival lengths. This combination might be a promising therapeutic treatment for patients with LAPC.

High-intensity focused ultrasound (HIFU) for pancreatic carcinoma: evaluation of feasibility, reduction of tumour volume and pain intensity

OBJECTIVES

Prognosis of patients with locally advanced pancreatic adenocarcinoma is extremely poor. They often suffer from cancer-related pain reducing their quality of life. This prospective observational study aimed to evaluate feasibility, local tumour response, and changes in quality of life and symptoms in Caucasian patients with locally advanced pancreatic cancer treated by ultrasound-guided high-intensity focused ultrasound (HIFU).

METHODS

Thirteen patients underwent HIFU, five with stage III, eight with stage IV UICC disease. Ten patients received simultaneous palliative chemotherapy. Postinterventional clinical assessment included evaluation of quality of life and symptom changes using standardized questionnaires. CT and MRI follow-up evaluated the local tumour response.

RESULTS

HIFU was successfully performed in all patients. Average tumour reduction was 34.2 % at 6 weeks and 63.9 % at 3 months. Complete or partial relief of cancer-related pain was achieved in 10 patients (77 %), five of whom required less analgesics for pain control. Quality of life was improved revealing increased global health status and alleviated symptoms. HIFU treatment was well tolerated. Eight patients experienced transient abdominal pain directly after HIFU.

CONCLUSIONS

HIFU ablation of pancreatic carcinoma is a feasible, safe and effective treatment with a crucial benefit in terms of reduction of tumour volume and pain intensity.

KEY POINTS

• US-guided HIFU is feasible and safe for patients with unresectable pancreatic cancer. • HIFU can considerably reduce tumour volume and cancer-related pain. • Patients treated with HIFU experienced significant and lasting reduction of pain intensity. • HIFU has a crucial clinical benefit for patients with pancreatic cancer.

Thermal therapy of pancreatic tumours using endoluminal ultrasound: Parametric and patient-specific modelling

PURPOSE

The aim of this study is to investigate endoluminal ultrasound applicator configurations for volumetric thermal ablation and hyperthermia of pancreatic tumours using 3D acoustic and biothermal finite element models.

MATERIALS AND METHODS

Parametric studies compared endoluminal heating performance for varying applicator transducer configurations (planar, curvilinear-focused, or radial-diverging), frequencies (1-5 MHz), and anatomical conditions. Patient-specific pancreatic head and body tumour models were used to evaluate feasibility of generating hyperthermia and thermal ablation using an applicator positioned in the duodenal or stomach lumen. Temperature and thermal dose were calculated to define ablation (> 240 EM(43 °C)) and moderate hyperthermia (40-45 °C) boundaries, and to assess sparing of sensitive tissues. Proportional-integral control was incorporated to regulate maximum temperature to 70-80 °C for ablation and 45 °C for hyperthermia in target regions.

RESULTS

Parametric studies indicated that 1-3 MHz planar transducers are the most suitable for volumetric ablation, producing 5-8 cm(3) lesion volumes for a stationary 5-min sonication. Curvilinear-focused geometries produce more localised ablation to 20-45 mm depth from the GI tract and enhance thermal sparing (T(max) < 42 °C) of the luminal wall. Patient anatomy simulations show feasibility in ablating 60.1-92.9% of head/body tumour volumes (4.3-37.2 cm(3)) with dose < 15 EM(43 °C) in the luminal wall for 18-48 min treatment durations, using 1-3 applicator placements in GI lumen. For hyperthermia, planar and radial-diverging transducers could maintain up to 8 cm(3) and 15 cm(3) of tissue, respectively, between 40-45 °C for a single applicator placement.

CONCLUSIONS

Modelling studies indicate the feasibility of endoluminal ultrasound for volumetric thermal ablation or hyperthermia treatment of pancreatic tumour tissue.

Retrospective analysis of high intensity focused ultrasound combined with S-1 in the treatment of metastatic pancreatic cancer after failure of gemcitabine

The purpose of this study was to verify the efficacy and safety of high intensity focused ultrasound therapy (HIFU) combined with S-1 in the treatment of metastatic pancreatic cancer after failure of gemcitabine (GEM). In total, 120 patients with GEM-refractory PC who received HIFU and S-1 between Aug 2012 and December 2014 were randomly assigned to 2 groups. The patients in group A (n = 61) received HIFU in combination with S-1 and those in group B (n = 59) were given S-1 alone. S-1 was administered orally twice a day on days 1-14. Cycles were repeated every 21 days. The follow up time was 3~19 months in both groups. The median overall survival (OS) time and progression free survival (PFS) were analysed by Kaplan-Meier method and Logrank test. The pain remission rate of the two groups was compared by χ(2) test. Patient characteristics and prognostic factors were compared. Patient characteristics did not significantly differ between the 2 groups. Median OS was significantly longer in group A (10.3 months) than in group B (6.6 months, P = 0.000). Median PFS was also significantly longer in group A than in group B (5.1 months vs 2.3 months, P = 0.000). Meanwhile, the pain remission rate was markedly higher in group A than in group B (57% vs. 20%, P = 0.000). There were mild side effects and no significant difference was observed between the two groups. The treatment effect was independently associated with a good outcome. HIFU in combination with S-1 might be effective and well tolerated as salvage chemotherapy in the treatment for metastatic pancreatic cancer.

Development of an endoluminal high-intensity ultrasound applicator for image-guided thermal therapy of pancreatic tumors

An ultrasound applicator for endoluminal thermal therapy of pancreatic tumors has been introduced and evaluated through acoustic/biothermal simulations and ex vivo experimental investigations. Endoluminal therapeutic ultrasound constitutes a minimally invinvasive conformal therapy and is compatible with ultrasound or MR-based image guidance. The applicator would be placed in the stomach or duodenal lumen, and sonication would be performed through the luminal wall into the tumor, with concurrent water cooling of the wall tissue to prevent its thermal injury. A finite-element (FEM) 3D acoustic and biothermal model was implemented for theoretical analysis of the approach. Parametric studies over transducer geometries and frequencies revealed that operating frequencies within 1-3 MHz maximize penetration depth and lesion volume while sparing damage to the luminal wall. Patient-specific FEM models of pancreatic head tumors were generated and used to assess the feasibility of performing endoluminal ultrasound thermal ablation and hyperthermia of pancreatic tumors. Results indicated over 80% of the volume of small tumors (~2 cm diameter) within 35 mm of the duodenum could be safely ablated in under 30 minutes or elevated to hyperthermic temperatures at steady-state. Approximately 60% of a large tumor (~5 cm diameter) model could be safely ablated by considering multiple positions of the applicator along the length of the duodenum to increase coverage. Prototype applicators containing two 3.2 MHz planar transducers were fabricated and evaluated in ex vivo porcine carcass heating experiments under MR temperature imaging (MRTI) guidance. The applicator was positioned in the stomach adjacent to the pancreas, and sonications were performed for 10 min at 5 W/cm² applied intensity. MRTI indicated over 40°C temperature rise in pancreatic tissue with heating penetration extending 3 cm from the luminal wall.