US-guided high-intensity focused ultrasound in pancreatic cancer treatment: a consensus initiative between Chinese and European HIFU centers

Purpose: Ultrasound-guided high-intensity focused ultrasound (USgHIFU) represents a safe and effective non-invasive thermoablative technique for managing inoperable pancreatic cancer. This treatment method significantly alleviates disease-related symptoms and reduces pancreatic tumor volume. However, the current body of evidence is constrained by a lack of randomized controlled trials. The utilization of USgHIFU is primarily indicated for patients with unresectable, locally advanced, or metastatic pancreatic cancer, particularly those experiencing symptoms due to a locally advanced primary tumor.Methods: This collaborative consensus paper, involving European and Chinese HIFU centers treating pancreatic cancer, delineates criteria for patient selection, focusing on those most likely to benefit from USgHIFU treatment. Consideration is given to endpoints encompassing symptom alleviation, local response rates, other oncological outcomes, as well as overall and progression-free survival. Additionally, this paper defines relevant contraindications, side effects, and complications associated with USgHIFU. The publication also explores the feasibility and role of USgHIFU within the context of palliative care, including standard systemic chemotherapy.Results: The non-invasive local treatment of advanced pancreatic cancer using HIFU should be regarded as an adjunctive option alongside systemic chemotherapy or best supportive care for managing this aggressive disease. Based on the ability of USgHIFU therapy to mitigate pain and reduce primary tumor volume, it should be considered as a complementary therapy for symptomatic patients with inoperable pancreatic cancer and as a potential means of tumor debulking. The underutilized yet promising USgHIFU exhibits the potential to enhance patients' quality of life by alleviating cancer-related pain. Experts in the field should evaluate this treatment option be evaluated by experts in this field, with this consensus paper potentially serving as a guiding resource for the medical community.Conclusions: US-guided HIFU for advanced pancreatic cancer addresses treatment goals, available options, success rates, and limitations. As a non-invasive, effective local therapy, complementary to chemotherapy and best supportive care, it plays a pivotal role in pain relief, reducing of tumor volume, and potentially improving survival rates.

Ultrasound-guided noninvasive pancreas ablation using histotripsy: feasibility study in an in vivo porcine model

Pancreatic cancer is a malignant disease associated with poor survival and nearly 80% present with unresectable tumors. Treatments such as chemotherapy and radiation therapy have shown overall improved survival benefits, albeit limited. Histotripsy is a noninvasive, non-ionizing, and non-thermal focused ultrasound ablation modality that has shown efficacy in treating hepatic tumors and other malignancies. In this novel study, we investigate histotripsy for noninvasive pancreas ablation in a pig model. In two studies, histotripsy was applied to the healthy pancreas in 11 pigs using a custom 32-element, 500 kHz histotripsy transducer attached to a clinical histotripsy system, with treatments guided by real-time ultrasound imaging. A pilot study was conducted in 3 fasted pigs with histotripsy applied at a pulse repetition frequency (PRF) of 500 Hz. Results showed no pancreas visualization on coaxial ultrasound imaging due to overlying intestinal gas, resulting in off-target injury and no pancreas damage. To minimize gas, a second group of pigs (n = 8) were fed a custard diet containing simethicone and bisacodyl. Pigs were euthanized immediately (n = 4) or survived for 1 week (n = 4) post-treatment. Damage to the pancreas and surrounding tissue was characterized using gross morphology, histological analysis, and CT imaging. Results showed histotripsy bubble clouds were generated inside pancreases that were visually maintained on coaxial ultrasound (n = 4), with 2 pigs exhibiting off-target damage. For chronic animals, results showed the treatments were well-tolerated with no complication signs or changes in blood markers. This study provides initial evidence suggesting histotripsy's potential for noninvasive pancreas ablation and warrants further evaluation in more comprehensive studies.

Therapeutic US Applications for the Abdomen and Pelvis

US and MRI-guided therapeutic US (TUS) can aid in the treatment of prostate, liver, and pancreatic cancer, as well as uterine fibroids and osseous metastases, and understanding the selection and optimization of treatment strategies is essential to furthering TUS advances and innovations.

First-in-man histotripsy of hepatic tumors: the THERESA trial, a feasibility study

Rationale Current hepatic locoregional therapies are limited in terms of effectiveness and toxicities. Given promising pre-clinical results, a first in-human trial was designed to assess the technical effectiveness and safety profile of histotripsy, a noninvasive, non-thermal, non-ionizing focused ultrasound therapy that creates precise, predictable tissue destruction, in patients with primary and secondary liver tumors.Methods A multicenter phase I trial (Theresa Study) was performed in a single country with 8 weeks of planned follow-up. Eight of fourteen recruited patients were deemed eligible and enrolled in the study. Hepatic histotripsy, was performed with a prototype system (HistoSonics, Inc., Ann Arbor, MI). Eleven tumors were targeted in the 8 patients who all had unresectable end-stage multifocal liver tumors: colorectal liver metastases (CRLM) in 5 patients (7 tumors), breast cancer metastases in 1 (1 tumor), cholangiocarcinoma metastases in 1 (2 tumors), and hepatocellular carcinoma (HCC) in 1 (1 tumor). The primary endpoint was acute technical success, defined as creating a zone of tissue destruction per planned volume assessed by MRI 1-day post-procedure. Safety (device-related adverse events) through 2 months was a secondary endpoint.Results The 8 patients had a median age of 60.4 years with an average targeted tumor diameter of 1.4 cm. The primary endpoint was achieved in all procedures. The secondary safety profile endpoint identified no device-related adverse events. Two patients experienced a continuous decline in tumor markers during the eight weeks following the procedure.Conclusions This first-in-human trial demonstrates that hepatic histotripsy effectively destroys liver tissue in a predictable manner, correlating very well with the planned histotripsy volume, and has a high safety profile without any device-related adverse events. Based on these results, the need for more definitive clinical trials is warranted. Trial Registration: Study to Evaluate VORTX Rx (Theresa). NCT03741088. https://clinicaltrials.gov/ct2/show/NCT03741088 KEY POINTSHistotripsy, a new noninvasive, non-thermal, non-ionizing focused ultrasound therapy, safely created a zone of tissue destruction in the liver that correlated very well with the pre-defined planned tissue destruction volume.In this first human trial histotripsy was well tolerated with no histotripsy device-related adverse events and its primary endpoint of acute technical success was achieved in all 8 enrolled patients with primary or secondary liver tumors.This new locoregional therapy for patients with liver tumors is safe and effective, warranting further trials.

Contrast-Enhanced Ultrasound: A Useful Tool to Study and Monitor Hepatic Tumors Treated With Histotripsy

Histotripsy is a novel noninvasive nonthermal, nonionizing, and precise treatment technique for tissue destruction. Contrast-enhanced ultrasound (CEUS) improves the detection, characterization, and follow-up of hepatic lesions because it depicts accurately the vascular perfusion of both normal hepatic tissue and hepatic tumors. We present the spectrum of imaging findings of CEUS after histotripsy treatment of hepatic tumors. CEUS provides real-time information, a close approximation to the dimension of the lesion, and a clear definition of its margins. Hepatic tumors detected by ultrasound can be potentially treated using B-mode ultrasound-guided histotripsy and characterized and monitored with CEUS. CEUS has shown to be very useful after tissue treatment to monitor and assess the evolution of the treated zone. Histotripsy treated zones are practically isoechogenic and slightly heterogeneous, and their limits are difficult to establish using standard B-mode ultrasound. The use of CEUS after histotripsy showing uptake of contrast protruding into the treated zone is clinically relevant to identify residual tumors and establish the most appropriate management strategy avoiding unnecessary treatments. We here describe CEUS findings after histotripsy for hepatic tumors.

Histotripsy for the Treatment of Cholangiocarcinoma Liver Tumors: In Vivo Feasibility and Ex Vivo Dosimetry Study

Histotripsy is a noninvasive, nonionizing, and nonthermal focused ultrasound ablation method that is currently being developed for the treatment of liver cancer. Promisingly, histotripsy has been shown for ablating primary [hepatocellular carcinoma (HCC)] and metastatic [colorectal liver metastasis (CLM)] liver tumors in preclinical and early clinical studies. The feasibility of treating cholangiocarcinoma (CC), a less common primary liver tumor that arises from the bile ducts, has not been explored previously. Given that prior work has established that histotripsy susceptibility is based on tissue mechanical properties, there is a need to explore histotripsy as a treatment for CC due to its dense fibrotic stromal components. In this work, we first investigated the feasibility of histotripsy for ablating CC tumors in vivo in a patient-derived xenograft mouse model. The results showed that histotripsy could generate CC tumor ablation using a 1-MHz small animal histotripsy system with treatment doses of 250, 500, and 1000 pulses/point. The second set of experiments compared the histotripsy doses required to ablate CC tumors to HCC and CLM tumors ex vivo. For this, human tumor samples were harvested after surgery and treated ex vivo with a 700-kHz clinical histotripsy transducer. Results demonstrated that significantly higher treatment doses were required to ablate CC and CLM tumors compared to HCC, with the highest treatment dose required for CC tumors. Overall, the results of this study suggest that histotripsy has the potential to be used for the ablation of CC tumors while also highlighting the need for tumor-specific treatment strategies.

Liver Histotripsy Mediated Abscopal Effect-Case Report

We present a case report that shows an abscopal effect in the context of a safety and efficacy clinical trial for histotripsy as ablation technique in liver tumors. The abscopal effect appears in the form of reduction in the volume of nontreated tumor lesions in the same organ, as well as sustained reduction of tumor marker [carcinoembryonic antigen (CEA)] that extends weeks away of the procedure. Histotripsy is a novel noninvasive, nonthermal, and nonionizing precise ablation technique for tissue destruction guided by ultrasonography. We discuss the feasibility of this technique compared with other focal therapies and its possibilities as immune system enhancer.

Ultrasound Guided High Intensity Focused Ultrasound for malignant tumors: The Spanish experience of survival advantage in stage III and IV pancreatic cancer

We described the experience of the HIFU Onco Unit of Hospital University Mutua Terrassa (Barcelona, Spain) treating malignant tumors, focusing on results of unresectable pancreatic tumors treated with Ultrasound Guided High Intensity Focused Ultrasound (USgHIFU) hyperthermia ablation in combination with adjuvant chemotherapy.

MATERIALS AND METHODS

From February 2008 to December 2013, we treated 140 malignant cases. Of those, 48 cases of unresectable pancreatic tumors were treated from March 2010 to December 2013, and the first 43 were included in the analysis. All the 43 cases (29 cases of stage III and 14 cases of stage IV) were treated with systemic chemotherapy. Clinical responses (thermical ablation achieved) were measured by image techniques, and complications were also recorded and analyzed.

RESULTS

The majority of the 140 cases treated at our HIFU center were pancreatic and liver tumors, among which 43 cases of pancreatic tumors were analyzed. Clinical responses (ablation obtained) were observed in 82% of the cases, and the responses lasted at 8 weeks post-procedure. We obtained 11 complete responses (25%) at the end of the combined treatment, nine from stage III patients and two from stage IV patients. Major complications included severe pancreatitis with GI bleeding (1), and skin burning of grade III that required plastic surgery (2). The median survival was 13 months (6 months-2.7 years). No deaths were registered during the course of the treatment.

CONCLUSIONS

HIFU is a potentially effective and safe modality for the treatment of malignant tumors. HIFU proves to have a survival advantage in treating unresectable pancreatic cancer.

Pharmacokinetics of the peritoneal-plasma barrier after systemic mitomycin C administration

The peritoneal plasma barrier (PPB) is a pharmacologic entity of importance for treatment planning in patients with malignant tumors confined to the abdominal cavity. We have examined the pharmacokinetics of the PPB by sampling abdominal fluid following intravenous mitomycin C (MMC) administration. The study included 15 cycles of treatment in seven patients with peritoneal carcinomatosis from colorectal cancer. Five patients were studied twice and one patient was studied three times for a total of 15 cycles. Patients were treated with intraperitoneal 5-fluorouracil (5-FU) at 20 mg/m2 in 11 of fluid. Between 250 and 500 ml of ascites remained after the 23 hour intraperitoneal dwell. On day 3, MMC (12 mg/m2) was administered intravenously as a 2-hour continuous infusion in 200 ml of dextrose solution. The concentration of MMC was determined in plasma, peritoneal fluid, and urine by high performance liquid chromatolography (HPLC) at frequent intervals for 8 hours. The area under the curve (AUC) for plasma as related to peritoneal fluid was three times greater for plasma in one cycle, two times greater for plasma in three cycles, 1.5 times greater for plasma in five cycles, and the same in six cycles. AUC ratios showed a correlation with the extent of peritoneal stripping at the prior surgical procedure 6 weeks to 14 weeks previously. We conclude that malignant ascites may be less exposed to chemotherapy than systemic tumor nodules when the intravenous route of drug administration is used. This inadequacy is even more pronounced in patients who have had extensive abdominal surgery.

Peritoneal carcinomatosis from gastrointestinal malignancy: natural history and new prospects for management

Peritoneal carcinomatosis represents regional spread of gastrointestinal, gynecological and other malignancies with or without evidence of systemic metastases. The authors reviewed the natural history and the different types of peritoneal carcinomatosis. A new treatment approach that combines cytoreductive surgery and intraperitoneal chemotherapy is described. The principles of this surgery and the pharmacology principles of intraperitoneal drug administration are explained. The major attraction of intraperitoneal therapy is that following intracavitary drug administration, the peritoneal cavity is exposed to higher concentrations than the rest of the body. A total of 100 patients with peritoneal carcinomatosis followed from one to ten years were treated by this approach. Patients were divided into four prognostic groups according to the histologic findings, extent of diseases, distant metastases and the completeness of cytoreductive surgery. This new cytoreductive approach is particularly effective for patients with low-grade malignancies confined to the abdominal cavity and who had a complete cytoreductive surgery.

Morbidity and mortality of cytoreductive surgery and intraperitoneal chemotherapy

BACKGROUND

Peritoneal carcinomatosis has been regarded as a uniformly lethal clinical entity. Recently, dose-intensive treatments combining cytoreductive surgery and intraperitoneal chemotherapy have resulted in long-term survival in selected patients.

METHODS

This article reports the morbidity and mortality associated with this new treatment strategy in 45 consecutive treatments of 43 patients with peritoneal carcinomatosis treated during an 18-month interval.

RESULTS

The duration of median postoperative ileus was 21 days, and increased age of the patient and extent of cytoreduction caused an increased incidence of ileus. Twenty-one complications occurred in 17 patients (37.7%). Complications related to enteric function included fistula (n = 4), bile leak (n = 1), pancreatitis (n = 1), and anastomotic disruption (n = 1). There were two early and two late episodes of postoperative bleeding requiring reoperation. Six patients had pneumonia and one had deep vein thrombosis. There were no deaths. Six of the seven complications related to enteric function occurred in patients who had undergone induction intraperitoneal chemotherapy before cytoreductive surgery plus early postoperative intraperitoneal chemotherapy.

CONCLUSIONS

As a result of these findings, induction intraperitoneal chemotherapy is only recommended for patients with low-volume intraabdominal cancer. In most patients surgical removal of peritoneal carcinomatosis before intraperitoneal chemotherapy is recommended. Because of the significant morbidity related to treatment of peritoneal carcinomatosis, careful patient selection and favorable long-term results of treatment are required.

Preoperative radiological evaluation of the liver by computerized tomographic portography in patients with hepatic tumors

The main objective of preoperative imaging studies is to define as accurately as possible the number, size, location, and relationship of tumor masses in the liver to pertinent portal and hepatic venous vasculature. Computerized tomographic portography images hepatic veins and segmental portal vein branches and identifies the anatomical location of tumor nodules with excellent sensitivity and a low false-positive rate. The intraoperative correlation of computerized tomographic portography on 30 patients in the last 20 months at this institution shows a sensitivity of 88 per cent with a low rate of false-positivity. The ability to detect metastatic lesions in the liver by computerized tomographic portography diminishes when the lesions are noted to be less than 1 cm. The authors conclude that the preoperative interpretation of the computerized tomographic portogram provides valuable information not previously available to the surgeon operating on the liver.