Microwave ablation of pancreatic head cancer: safety and efficacy. J Vasc Interv Radiol. 2013;24:1513-1520. [PMID: 24070507 DOI: 10.1016/j.jvir.2013.07.005]

Local ablative therapies and the effect on antitumor immune responses in pancreatic cancer - A review

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease, projected to rank as the second most prevalent cause of cancer-related mortality by 2030. Despite significant progress in advances in surgical techniques and chemotherapy protocols, the overall survival (OS) remains to be less than 10 % for all stages combined. In recent years, local ablative techniques have been introduced and utilized as additional therapeutic approaches for locally advanced pancreatic cancer (LAPC), with promising results with respect to local tumor control and OS. In addition to successful cytoreduction, there is emerging evidence that local ablation induces antitumor immune activity that could prevent or even treat distant metastatic tumors. The enhancement of antitumor immune responses could potentially make ablative therapy a therapeutic option for the treatment of metastatic PDAC. In this review, we summarize current ablative techniques used in the management of LAPC and their impact on systemic immune responses.

Advancements in Microwave Ablation Techniques for Managing Pancreatic Lesions

Thermal ablation, including microwave ablation, has become increasingly important in the management of many solid tumors, including primary and metastatic tumors of the liver, kidney, and lung. However, its adoption to treat pancreatic lesions has been slowed due to concerns about potential adverse events. The success of radiofrequency ablation (RFA) in inoperable pancreatic cancers paved the way for its use in pancreatic neuroendocrine tumors and pancreatic cystic neoplasms (PCLs). In the last decade, other thermal ablation techniques, like microwave ablation, have emerged as alternatives to RFA. Microwaves, with frequencies ranging from 900 to 2450 MHz, generate heat by rapidly oscillating water molecules. Microwave ablation's advantage lies in its ability to achieve higher intra-lesion temperatures and uniform heating compared with RFA. Microwave ablation's application in pancreatic cancer and pancreatic neuroendocrine tumors has demonstrated promise with similar technical success to RFA. Yet, concern for peri-procedure complications, as well as a dearth of studies comparing RFA and microwave ablation, emphasize the need for further research. No studies have evaluated microwave ablation in PCLs. We herein review thermal ablation's potential to treat pancreatic lesions.

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.

Role of Therapeutic Endoscopic Ultrasound in Management of Pancreatic Cancer: An Endoscopic Oncologist Perspective

Pancreatic cancer is a highly lethal disease with an aggressive clinical course. Patients with pancreatic cancer are usually asymptomatic until significant progression of their disease. Additionally, there are no effective screening guidelines for pancreatic cancer in the general population. This leads to a delay in diagnosis and treatment, resulting in poor clinical outcomes and low survival rates. Endoscopic Ultrasound (EUS) is an indispensable tool for the diagnosis and staging of pancreatic cancer. In the modern era, with exponential advancements in technology and device innovation, EUS is also being increasingly used in a variety of therapeutic interventions. In the context of pancreatic cancer where therapies are limited due to the advanced stage of the disease at diagnosis, EUS-guided interventions offer new and innovative options. Moreover, due to their minimally invasive nature and ability to provide real-time images for tumor localization and therapy, they are associated with fewer complication rates compared to conventional open and laparoscopic approaches. In this article, we detail the most current and important therapeutic applications of EUS for pancreatic cancer, namely EUS-guided Fine Needle Injections, EUS-guided Radiotherapy, and EUS-guided Ablations. Furthermore, we also discuss the feasibility and safety profile of each intervention in patients with pancreatic cancer to provide gastrointestinal medical oncologists, radiation and surgical oncologists, and therapeutic endoscopists with valuable information to facilitate patient discussions and aid in the complex decision-making process.

Endoscopic Ultrasound-Guided Local Ablative Therapies for the Treatment of Pancreatic Neuroendocrine Tumors and Cystic Lesions: A Review of the Current Literature

Since its emergence as a diagnostic modality in the 1980s, endoscopic ultrasound (EUS) has provided the clinician profound access to gastrointestinal organs to aid in the direct visualization, sampling, and subsequent identification of pancreatic pathology. In recent years, advancements in EUS as an interventional technique have promoted the use of local ablative therapies as a minimally invasive alternative to the surgical management of pancreatic neuroendocrine tumors (pNETs) and pancreatic cystic neoplasms (PCNs), especially for those deemed to be poor operative candidates. EUS-guided local therapies have demonstrated promising efficacy in addressing a spectrum of pancreatic neoplasms, while also balancing local adverse effects on healthy parenchyma. This article serves as a review of the current literature detailing the mechanisms, outcomes, complications, and limitations of EUS-guided local ablative therapies such as chemical ablation and radiofrequency ablation (RFA) for the treatment of pNETs and PCNs, as well as a discussion of future applications of EUS-guided techniques to address a broader scope of pancreatic pathology.

Interventional Radiology in the Treatment of Pancreatic Adenocarcinoma: Present and Future Perspectives

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease; patients' long-term survival is strictly linked to the surgical resection of the tumor but only a minority of patients (2-3%) have a resectable disease at diagnosis. In patients with surgically unresectable disease, interventional radiology is taking on an increasing role in treatment with the application of loco-regional percutaneous therapies. The primary purposes of this narrative review are to analyze the safety and efficacy of ablative techniques in the management of borderline resectable and locally advanced diseases and to underline the role of the interventional radiologist in the management of patients with distant metastases. The secondary purpose is to focus on the synergy between immunotherapy and ablative therapies.

Can local ablative techniques replace surgery for locally advanced pancreatic cancer?

In the treatment of pancreatic ductal adenocarcinoma (PDAC) the best chance at long term survival or cure has to date always included the complete surgical removal of the tumor. However, locally advanced pancreatic cancer (LAPC), about 25% of all newly diagnosed PDAC, is defined by its primary technical unresectability due to infiltration of visceral arteries and absence of metastasis. Induction therapies, especially FOLFIRINOX treatment, together with technical surgical advancement have increased the numbers for conversion to secondary resectability. Recent data on resections after induction therapy show promising, almost doubled survival compared to palliative treatment. Yet, around 70% of LAPC remain unresectable after induction therapy, often due to persistent local invasion. As locally ablative techniques are becoming more widely available this review examines their possible applicability to substitute for surgery in these cases which we propose to group under the new term "Inconvertible LAPC". The need for defining this novel subgroup who might benefit from ablative treatment is based on the findings in our review that high-level evidence on ablative techniques for PDAC is largely lacking and the latest effective, harmonized treatment guidelines for LAPC are not often incorporated in these studies. The "inconvertible LAPC" label requires persistent unresectability after staging and induction therapy of LAPC according to current guidelines followed by liberal indication for aggressive surgical exploration at a center equipped for extended pancreatic resections. Ideally, this specification of a new, distinct patient group will also put it in the spotlight more, hopefully prompt more trials designed to generate robust evidence and optimize transferability of study results.

Open radiofrequency ablation as upfront treatment for locally advanced pancreatic cancer: Requiem from a randomized controlled trial

BACKGROUND

Local ablation of pancreatic cancer has been suggested as an option to manage locally advanced pancreatic cancer (LAPC) although no robust evidence has been published to date to support its application. The aim of this study is to compare overall survival (OS) and progression-free survival (PFS) in patients receiving both radiofrequency ablation (RFA) and conventional chemoradiotherapy (CHRT) with patients receiving CHRT only.

METHODS

This is a multicentre prospective randomized controlled trial (RCT). Patients with LAPC diagnosed by the Pancreas-Ablation-Team-Verona were randomly assigned to open RFA (Group A) or CHRT (Group B). Survival analyses were performed using the Kaplan-Meier method and compared using the log-rank test. Statistical significance was set at p < 0.05.

RESULTS

One hundred LAPC patients were enrolled from January 2014 to August 2016. 33% of patients in Group A did not receive the designated procedure because of intraoperative findings of liver (18.7%) or peritoneal metastases (43.8%), or technical contraindications (37.5%). We did not observe any statistically significant survival benefit from RFA compared to CHRT, neither in terms of OS (medians of 14.2 months and 18.1 months, respectively, p = 0.639) nor PFS (medians of 8 months and 6 months respectively, p = 0.570). Mortality was nil and RFA-related morbidity was 15.6%. In 13% of subjects, conversion to surgery occurred (2 after RFA and 11 after CHRT).

CONCLUSIONS

This is the first RCT evaluating the impact of upfront RFA in the multimodal treatment of LAPC. Compared to CHRT, RFA alone did not provide any advantage in terms of OS or PFS. It could be considered as a therapeutic option for LAPC within a multimodal context and after neoadjuvant therapies.

A Multicenter Randomized Controlled Prospective Study to Assess Efficacy of Laparoscopic Electrochemotherapy in the Treatment of Locally Advanced Pancreatic Cancer

Background: Eighty percent of patients with pancreatic adenocarcinoma present a locally advanced or metastatic disease at diagnosis and are not eligible for surgery if not with palliative intent. In cases of locally advanced disease (LAPC), the combination of chemo and radiotherapy is the only therapeutic option and correlates with a median survival of 15 months (10 months without treatment), with partial remission of disease in 50% of cases. The feasibility and safety of Electrochemotherapy (ECT) have been demonstrated in the treatment of deep tumors. Aim: The aim of the study is to evaluate the efficacy of electrochemotherapy (ECT) followed by conventional systemic treatment compared to the only conventional systemic treatment in LAPC in terms of objective response and overall survival. Patients and Methods: This study is a phase IIb prospective multicenter randomized controlled trial with two arms. The study will include 90 patients: 45 in the control group and 45 in the experimental group. Patients with LAPC in the control arm will receive conventional chemotherapy (FOLFOXIRI). Patients with LAPC in the experimental arm will be subjected to Electrochemotherapy and subsequently to FOLFOXIRI. The objective response at 30, 90, and 180 days from treatment will be based on the computed tomography (CT), magnetic resonance (MR), and positron emission tomography/CT response (PET/CT). The objective long-term treatment response will be evaluated with the modified response evaluation criteria in solid tumors (m-RECIST) criteria, which will take into account the difference in vascularization, determined by the images obtained by CT and MR of the tumor treated before and after ECT. Conclusions: Not resectable liver metastasis, pancreatic tumors, and locally advanced renal carcinomas can be treated with laparoscopic electrodes. ECT could represent an effective therapeutic option for patients not eligible for surgery susceptible to be managed only with palliative therapies.

Minimally invasive image-guided therapy of primary and metastatic pancreatic cancer

Pancreatic cancer is a challenging malignancy with limited treatment options and poor life expectancy. The only curative option is surgical resection, but only 15%-20% of patients are resectable at presentation because more than 50% of patients has distant metastasis at diagnosis and the rest of them has locally advanced pancreatic cancer (LAPC). The standard of care first line treatment for LAPC patients is chemotherapy with or without radiation therapy. Recent developments in minimally invasive ablative techniques may add to the treatment armamentarium of LAPC. There are increasing number of studies evaluating these novel ablative techniques, including radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation. Most studies which included pancreatic tumor ablation, demonstrated improved overall survival in LAPC patients. However, the exact protocols are yet to set up to which stage of the treatment algorithm ablative techniques can be added and in what kind of treatment combinations. Patients with metastatic pancreatic cancer has dismal prognosis with 5-year survival is only 3%. The most common metastatic site is the liver as 90% of pancreatic cancer patients develop liver metastasis. Chemotherapy is the primary treatment option for patients with metastatic pancreatic cancer. However, when the tumor is not responding to chemotherapy or severe drug toxicity develops, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease progression and improve survival in selected patients. During the last decade new therapeutic options arose with the advancement of minimally invasive technologies to treat pancreatic cancer patients. These new therapies have been a topic of increasing interest due to the severe prognostic implications of locally advanced and metastatic pancreatic cancer and the low comorbid risk of these procedures. This review summarizes new ablative options for patients with LAPC and percutaneous liver-directed therapies for patients with liver-dominant metastatic disease.

Feasibility and efficacy of microwave ablation for treating breast fibroadenoma

BACKGROUND

To investigate the safety, efficacy, and follow-up outcomes of microwave ablation (MWA) in patients with breast fibroadenoma.

METHODS

An institutional review board-approved this study of patients treated with MWA for breast fibroadenoma from October 2017 to March 2019. Clinical features of patients and breast fibroadenoma were analyzed. At follow-up all patients received physical examination and ultrasound imaging.

RESULTS

In total, 171 patients with 271 lesions were enrolled. The mean lesion diameter was 1.35 ± 0.47 cm. The results revealed differential lesion states, including stability, enlargement, reduction, and complete regression, at 1-6, 6-12, and >12 months of follow-up. The size was reduced in 22.14% (31/140), 26.36% (29/110), and 36.36% (16/44) of the lesions at 1-6, 6-12, and >12 months of follow-up, respectively. The proportion of lesions with complete regression was 24.29% (34/140) at 1-6 months, 45.45% (50/110) at 6-12 months, and 40.91% (18/44) at >12 months of follow up. There was no significant relationship between the curative effect and age, lesion location, and blood flow in patients with breast fibroadenoma after MWA (p > .05), but there was statistically significant relationship with lesion diameter (categorized as <1.5 cm and ≥1.5 cm) (p < .05).

CONCLUSIONS

The current evidence indicates that MWA is a safe and effective method for treating breast fibroadenoma. Nevertheless, further large-scale prospective trials and well-designed future studies are warranted to validate our findings.

Local ablation of pancreatic tumors: State of the art and future perspectives

BACKGROUND

Currently, the technologies most commonly used to treat locally advanced pancreatic cancer are radiofrequency ablation (RFA), microwave ablation, and irreversible (IRE) or reversible electroporation combined with low doses of chemotherapeutic drugs.

AIM

To report an overview and updates on ablative techniques in pancreatic cancer.

METHODS

Several electronic databases were searched. The search covered the years from January 2000 to January 2021. Moreover, the reference lists of the found papers were analysed for papers not indexed in the electronic databases. All titles and abstracts were analysed.

RESULTS

We found 30 studies (14 studies for RFA, 3 for microwave therapy, 10 for IRE, and 3 for electrochemotherapy), comprising 1047 patients, which were analysed further. Two randomized trials were found for IRE. Percutaneous and laparotomy approaches were performed. In the assessed patients, the median maximal diameter of the lesions was in the range of 2.8 to 4.5 cm. All series included patients unfit for surgical treatment, but Martin et al assessed a subgroup of patients with borderline resectable tumours who underwent resection with margin attenuation with IRE. Most studies administered chemotherapy prior to ablative therapies. However, several studies suggest that the key determinant of improved survival is attributable to ablative treatment alone. Nevertheless, the authors suggested chemotherapy before local therapies for several reasons. This strategy may not only downstage a subgroup of patients to curative-intent surgery but also support to recognize patients with biologically unfavourable tumours who would likely not benefit from ablation treatments. Ablation therapies seem safe based on the 1047 patients assessed in this review. The mortality rate ranged from 1.8% to 2%. However, despite the low mortality, the reported rates of severe post procedural complications ranged from 0%-42%. Most reported complications have been self-limiting and manageable. Median overall survival varied between 6.0 and 33 mo. Regarding the technical success rate, assessed papers reported an estimated rate in the range of 85% to 100%. However, the authors reported early recurrence after treatment. A distinct consideration should be made on whether local treatments induce an immune response in the ablated area. Preclinical and clinical studies have shown that RFA is a promising mechanism for inducing antigen-presenting cell infiltration and enhancing the systemic antitumour T-cell immune response and tumour regression.

CONCLUSION

In the management of patients with pancreatic cancer, the possibility of a multimodal approach should be considered, and conceptually, the combination of RFA with immunotherapy represents a novel angle of attack against this tumour.

Role of radio-ablative technique for optimizing the survival of patients with locally advanced pancreatic adenocarcinoma (Review)

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common and frequently diagnosed malignant tumor of the pancreas with few treatment options and poor life expectancy. Despite the advances in the surgical field, 40% of the patients are diagnosed with locally advanced disease which is not suitable for surgery. Radio-frequency ablation (RFA) has been described as a new ‘weapon’ in the multimodal treatment of PDAC, representing a cytoreductive procedure which must be completed with radiotherapy or chemo-radiotherapy. A systematic research was carried out utilizing the PubMed database in regards to this subject, to evaluate the role of RFA in PDAC management. Abstracts, letters-to-the-editor and non-English language manuscripts were excluded. The literature showed that RFA can be used in open and laparoscopic surgery but it is also feasible for endoscopic ultrasound (EUS-guided RFA) or percutaneous approach. Even though we found optimistic and encouraging reports on overall survival (OS), randomized studies are still required to corroborate these findings. Our review research underline that surgical resection remains the only radical treatment option, RFA being a safe and feasible technique reserved for unresectable, non-metastatic pancreatic tumors. Its combination with oncological treatment can improve the OS of these patients.

Ablation in Pancreatic Cancer: Past, Present and Future

The insidious onset and aggressive nature of pancreatic cancer contributes to the poor treatment response and high mortality of this devastating disease. While surgery, chemotherapy and radiation have contributed to improvements in overall survival, roughly 90% of those afflicted by this disease will die within 5 years of diagnosis. The developed ablative locoregional treatment modalities have demonstrated promise in terms of overall survival and quality of life. In this review, we discuss some of the recent studies demonstrating the safety and efficacy of ablative treatments in patients with locally advanced pancreatic cancer.

Locally Advanced Pancreatic Cancer: Percutaneous Management Using Ablation, Brachytherapy, Intra-arterial Chemotherapy, and Intra-tumoral Immunotherapy

PURPOSE OF REVIEW

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplasms, bearing a terrible prognosis. Stage III tumors, also known as locally advanced pancreatic cancer (LAPC), are unresectable, and current palliative chemotherapy regimens have only modestly improved survival in these patients. At this stage of disease, interventional techniques may be of value and further prolong life. The aim of this review was to explore current literature on locoregional percutaneous management for LAPC.

RECENT FINDINGS

Locoregional percutaneous interventional techniques such as ablation, brachytherapy, and intra-arterial chemotherapy possess cytoreductive abilities and have the potential to increase survival. In addition, recent research demonstrates the immunomodulatory capacities of these treatments. This immune response may be leveraged by combining the interventional techniques with intra-tumoral immunotherapy, possibly creating a durable anti-tumor effect. This multimodality treatment approach is currently being examined in several ongoing clinical trials. The use of certain interventional techniques appears to improve survival in LAPC patients and may work synergistically when combined with immunotherapy. However, definitive conclusions can only be made when large prospective (randomized controlled) trials confirm these results.

Establishing an immunocompromised porcine model of human cancer for novel therapy development with pancreatic adenocarcinoma and irreversible electroporation

New therapies to treat pancreatic cancer are direly needed. However, efficacious interventions lack a strong preclinical model that can recapitulate patients’ anatomy and physiology. Likewise, the availability of human primary malignant tissue for ex vivo studies is limited. These are significant limitations in the biomedical device field. We have developed RAG2/IL2RG deficient pigs using CRISPR/Cas9 as a large animal model with the novel application of cancer xenograft studies of human pancreatic adenocarcinoma. In this proof-of-concept study, these pigs were successfully generated using on-demand genetic modifications in embryos, circumventing the need for breeding and husbandry. Human Panc01 cells injected subcutaneously into the ears of RAG2/IL2RG deficient pigs demonstrated 100% engraftment with growth rates similar to those typically observed in mouse models. Histopathology revealed no immune cell infiltration and tumor morphology was highly consistent with the mouse models. The electrical properties and response to irreversible electroporation of the tumor tissue were found to be similar to excised human pancreatic cancer tumors. The ample tumor tissue produced enabled improved accuracy and modeling of the electrical properties of tumor tissue. Together, this suggests that this model will be useful and capable of bridging the gap of translating therapies from the bench to clinical application.

Computed Tomography-Guided Percutaneous Radiofrequency Ablation of the Splanchnic Nerves as a Single Treatment for Pain Reduction in Patients with Pancreatic Cancer

The aim of this paper is to prospectively evaluate the efficacy and safety of percutaneous computed tomography (CT)-guided radiofrequency (RF) neurolysis of splanchnic nerves as a single treatment for pain reduction in patients with pancreatic cancer. Patients with pancreatic ductal adenocarcinoma suffering from abdominal pain refractory to conservative medication who underwent CT-guided neurolysis of splanchnic nerves by means of continuous radiofrequency were prospectively evaluated for pain and analgesics reduction as well as for survival. In all patients, percutaneous neurolysis was performed with a bilateral retrocrural paravertebral approach at T12 level using a 20 Gauge RF blunt curved cannula with a 1cm active tip electrode. Self-reported pain scores were assessed before and at the last follow-up using a pain inventory with numeric visual scale (NVS) units. The mean patient age was 65.4 ± 10.8 years (male-female: 19-11). The mean pain score prior to RF neurolysis of splanchnic nerves was 9.0 NVS units; this score was reduced to 2.9, 3.1, 3.6, 3.8, and 3.9 NVS units at 1 week, 1, 3, 6, and 12 months respectively (p < 0.001). Significantly reduced analgesic usage was reported in 28/30 patients. Two grade I complications were reported according to the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) classification system. According to the results of the present study, solely performed computed tomography-guided radiofrequency neurolysis of splanchnic nerves can be considered a safe and efficacious single-session technique for pain palliation in patients with pancreatic ductal adenocarcinoma suffering from abdominal pain refractory to conservative medication. Although effective in pain reduction the technique seems to have no effect upon survival improvement.

Assessment of Ablation Therapy in Pancreatic Cancer: The Radiologist's Challenge

This article provides an overview of imaging assessment of ablated pancreatic cancer. Only studies reporting radiological assessment on pancreatic ablated cancer were retained. We found 16 clinical studies that satisfied the inclusion criteria. Radiofrequency ablation and irreversible electroporation have become established treatment modalities because of their efficacy, low complication rates, and availability. Microwave Ablation (MWA) has several advantages over radiofrequency ablation (RFA), which may make it more attractive to treat pancreatic cancer. Electrochemotherapy (ECT) is a very interesting emerging technique, characterized by low complication rate and safety profile. According to the literature, the assessment of the effectiveness of ablative therapies is difficult by means of the Response Evaluation Criteria in Solid Tumors (RECIST) criteria that are not suitable to evaluate the treatment response considering that are related to technique used, the timing of reassessment, and the imaging procedure being used to evaluate the efficacy. RFA causes various appearances on imaging in the ablated zone, correlating to the different effects, such as interstitial edema, hemorrhage, carbonization, necrosis, and fibrosis. Irreversible electroporation (IRE) causes the creation of pores within the cell membrane causing cell death. Experimental studies showed that Diffusion Weigthed Imaging (DWI) extracted parameters could be used to detect therapy effects. No data about functional assessment post MWA is available in literature. Morphologic data extracted by Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) do not allow to differentiate partial, complete, or incomplete response after ECT conversely to functional parameters, obtained with Position Emission Tomography (PET), MRI, and CT.

The role of interventional radiology in the treatment of patients with pancreatic cancer

Interventional radiology (IR) provides minimally invasive therapeutic and palliative options for the treatment of pancreatic cancer depending on the stage of the disease. IR plays a critical, and also a very effective role, in both pre- and post-operative care of the patients with early stage resectable disease and also in palliative treatment of the patients with locally advanced or metastatic disease. In this article, we aimed to present the capability and the limitations of IR procedures including: local treatment options of primary and metastatic pancreatic cancer, palliation of biliary and intestinal obstructions, minimally invasive treatment of post-operative complications, and pain management.

Imaging response evaluation after local ablative treatments in locally advanced pancreatic cancer: an expedited systematic review

BACKGROUND

Several local ablative modalities have been introduced for the treatment of locally advanced pancreatic cancer (LAPC). However, there is no consensus on how to evaluate the imaging response after treatment. A systematic review was performed regarding the use of imaging for response assessment in LAPC.

METHODS

A systematic literature search was conducted in PubMed. Studies reporting imaging outcomes were included in the review. Studies were excluded if the imaging outcomes could not be differentiated between different disease stages, tumor histology or surgical approaches.

RESULTS

Thirty-four studies were included in the analysis. Fourteen studies used standardized response criteria, while six studies did not report the response evaluation method. The rest used self-determined criteria, absolute size comparisons or similar methods. One study found a correlation between early systemic progression (<6 months) and overall survival.

CONCLUSION

There was notable variation in the use of imaging for response assessment in LAPC. This significantly hinders cross-comparison of results among studies. There is currently only sparse evidence of an association between imaging responses and overall survival. The field calls for standardized recommendations regarding the choice of response assessment method, timing of scans, target definition and reporting of outcomes.

[Ablative treatment options for locally advanced unresectable and borderline resectable pancreatic carcinoma]

BACKGROUND

Locally advanced unresectable (nonmetastatic) and borderline resectable pancreatic carcinomas represent a therapeutic challenge. Several minimally invasive local ablative techniques are available for local treatment in these situations.

OBJECTIVE

Which interventional techniques and application options are currently available for pancreatic carcinoma and which oncological results could be achieved so far?

MATERIAL AND METHODS

An analysis of reviews and studies was carried out. The selection of literature was based on searches in PubMed and the Cochrane library. The studies analyzed were reviews, meta-analyses and original articles mainly from the period between 2013 and 2018. Single case reports were not included in this review.

RESULTS

Local ablative techniques are performed with various forms of energy and are associated with specific advantages and disadvantages. They have to be individually tailored to the specific patient and situation. Noninvasive thermal ablation with high-intensity focused ultrasound (HIFU) is primarily used for palliative pain relief. Solid tumors are the main indication for thermal necrosis with microwave ablation (MWA) and radiofrequency ablation (RFA). The use of irreversible electroporation (IRE) enables a selective destruction of tumor cells and can be performed in the vicinity of sensitive structures. This technique is applied for primary tumor control and also for accentuation of tumor margins during resection.

CONCLUSION

With local ablative techniques an improvement in the quality of life and possibly the prognosis can be achieved in patients with unresectable pancreatic cancer; however, the latter aspect has to be viewed with caution due to a current lack of well-founded data.

Efficacy and safety of CT-guided high-dose-rate interstitial brachytherapy in primary and secondary malignancies of the pancreas

PURPOSE

To evaluate efficacy and safety of CT-guided iBT in patients with primary and secondary malignancies of the pancreas.

MATERIAL AND METHODS

13 patients with 13 lesions of the pancreatic corpus and tail were included: 8 secondary malignancies (metastatic lesions = ML) and 5 primary malignancies, including 3 primary tumors (PT) and 2 isolated locoregional recurrences (ILR) after surgical resection were treated with image-guided iBT using a 192iridium source (single fraction irradiation). Every 3 months after treatment clinical and imaging follow-up were conducted to evaluate efficacy. Peri- and postinterventional complications were assessed descriptively.

RESULTS

The median diameter of the gross tumor volume (GTV) was 3 cm (range 1-6.5 cm), treated with a median D100 (minimal enclosing tumor dose) of 15.3 Gy (range 9.2-25.4 Gy). Local tumor control (LTC) was 92.3% within a median follow-up period of 6.7 months (range 3.2-55.7 months). Cumulative median progression free survival (PFS) was 6.2 months (range 2.8-25.7 months; PFS of primary and secondary malignancies was 5.8 and 6.2 months, respectively). Cumulative median over all survival (OS) after iBT was 16.2 months (range 3.3-55.7 months; OS of primary and secondary malignancies was 7.4 months and 45.6 months, respectively). 1 patient developed mild acute pancreatits post iBT, spontanously resolved within 1 week. No severe adverse events (grade 3+) were recorded.

CONCLUSION

Image-guided iBT is a safe and particularly effective treatment in patients with primary and secondary malignancies of the pancreas and might provide a well-tolerated additional therapeutic option in the multidisciplinary management of selected patients.

Ultrasound-guided percutaneous procedures in pancreatic diseases: new techniques and applications

Ultrasound (US) is not only an important diagnostic tool for the evaluation of the pancreas, but is also a fundamental imaging technique to guide percutaneous interventions for several pancreatic diseases (fluid aspiration and drainage; invasive diagnosis by means fine-needle aspiration and core-needle biopsy; tumour ablation by radiofrequency, microwaves, irreversible electroporation, cryoablation, and high-intensity focused US). Technical improvements, such as contrast media and fusion imaging, have recently increased precision and safety and reduced procedure-related complications. New treatment US techniques for the ablation of pancreatic tumours, such as contrast-enhanced US and multimodality fusion imaging, have been recently developed and have elicited a growing interest worldwide. The purpose of this article was to review the most up-to-date role of US in percutaneous procedures for pancreatic diseases.

Ablation treatments in unresectable pancreatic cancer

Ablation treatments have been increasingly applied as an alternative treatment for unresectable locally advanced pancreatic cancer (LAPC). The goal of LAPC therapy is surgical resection with negative margins (R0); however, that can be achieved only in a minority of patients and only following neoadjuvant treatment. Ablation might be useful for those patients with unresectable LAPC that do not progress towards metastatic stage and do not experience a true downstaging. Indeed, some LAPC that tend to grow locally, might be the subgroup of tumors that could benefit from ablation. Experience is necessary to select patients and the technique to adopt, since serious or fatal complications can occur. This review aims to discuss the role of ablation treatments in LAPC, with a unique focus on radiofrequency ablation and irreversible electroporation.

Thermal ablation of pancreatic cancer: A systematic literature review of clinical practice and pre-clinical studies

PURPOSE

Pancreatic cancer is a challenging malignancy with low treatment option and poor life expectancy. Thermal ablation techniques were proposed as alternative treatment options, especially in advanced stages and for unfit-for-surgery patients. This systematic review describes the thermal ablative techniques -i.e., Laser (LA), Radiofrequency (RFA), Microwave (MWA) Ablation, High-Intensity Focused Ultrasound (HIFU) and cryoablation- available for pancreatic cancer treatment. Additionally, an analysis of the efficacy, complication rate and overall survival for each technique is conducted.

MATERIAL AND METHODS

This review collects the ex vivo, preclinical and clinical studies presenting the use of thermal techniques in the pancreatic cancer treatment, searched up to March 2018 in PubMed and Medline. Abstracts, letters-to-the-editor, expert opinions, reviews and non-English language manuscripts were excluded.

RESULTS

Sixty-five papers were included. For the ex vivo and preclinical studies, there are: 12 records for LA, 8 for RFA, 0 for MWA, 6 for HIFU, 1 for cryoablation and 3 for hybrid techniques. For clinical studies, 1 paper for LA, 14 for RFA, 1 for MWA, 17 for HIFU, 1 for cryoablation and 1 for hybrid techniques.

CONCLUSIONS

Important technological advances are presented in ex vivo and preclinical studies, as the real-time thermometry, nanotechnology and hybrid techniques to enhance the thermal outcome. Conversely, a lack of standardization in the clinical employment of the procedures emerged, leading to contrasting results on the safety and feasibility of some analyzed techniques. Uniform conclusions on the safety and feasibility of these techniques for pancreatic cancer will require further structured investigation.

Neutralizing TGF-β promotes anti-tumor immunity of dendritic cells against pancreatic cancer by regulating T lymphocytes

Previous fundamental or clinical trials of dendritic cell (DC) vaccine against pancreatic ductal adenocarcinoma (PDAC) revealed the burgeoning neoadjuvant immunotherapy. Microarray studies indicated that multiple ingredients of the transfer growth factor beta (TGF-β) pathway were overexpressed in PDAC, which inhibited the intratumoral immune response. To explore whether the DC volume in tumor microenvironment contributes to the differentiation of T cell cohort and test the hypothesis that combining DC vaccine with TGF-β inhibitors will elevate the anti-tumor immune response, we managed to co-culture T cells in vitro with pancreatic cancer cells and DCs in different concentrations, and combine TGF-β blockage with DC vaccine therapy in a murine model of pancreatic cancer. In in vitro studies, we discovered that CD8⁺ T cytotoxic cell (Tc) presented a significant advantage and lower volume of CD4⁺ T helper cell (Th) existed with a certain elevated DC concentration (p < 0.05), associated with declined interleukin (IL)-10 and increased interferon (IFN)-γ, which suggested with the DC volume increasing, the enhancing immune effect may represent a great advantage in such a system (p < 0.05). When interfered with anti-TGF-β antibody or TGF-β cytokine, respectively, in the co-culture system, we found IFN-γ producing was extremely higher and T cell apoptosis relatively descent with TGF-β blockage (p < 0.05). The murine PDAC model demonstrated a survival advantage treated with anti-TGF-β antibody combined with DC vaccine when compared with monotherapy controls (p < 0.05). Therefore, these findings indicated that, through neutralizing TGF-β associated with DC vaccine, the anti-tumor immunity is highly elevated and this combinational therapy will provide an efficacious prospect.

Irreversible Electroporation in Patients with Pancreatic Cancer: How Important Is the New Weapon?

Background

Pancreatic cancer (PC) is a deadly disease with poor prognosis in the general population. We aimed to quantitate overall survival of patients with PC after irreversible electroporation (IRE) and the incidence of relevant complications.

Methods

We performed a literature search via five electronic databases (PubMed, Embase, Web of Science, Scopus, and Cochrane Library databases) up to August 2017. The primary outcomes were overall survival and prognosis. Secondary outcomes included the response of post-IRE complications. Fixed-effects or random-effects meta-analysis was conducted to pool these data.

Results

A total of 15 eligible articles involving 535 patients were included. The primary outcomes showed that the pooled prevalence estimates of overall survival were 94.1% (95% CI: 90.7–97.5), 80.9% (95% CI: 72.5–89.4), 54.5% (95% CI: 38.3–70.6), and 33.8% (95% CI: 14.2–53.5) at 3, 6, 12, and 24 months, and the pooled prevalence data of complete response (CR) at 2 months, partial response (PR) at 3 months, and progression at 3 months were 12.5% (95% CI: 2.9–22.2), 48.5% (95% CI: 39.4–57.6), and 19.7% (95% CI: 7.3–32.2), respectively. The secondary outcomes showed that the pooled prevalence values of post-IRE complications were abscess 6.6% (95% CI: 0.2–13), fistula 10.6% (95% CI: 2.5–18.7), pain 33.5% (95% CI: 14.5–52.5), infection 16.1% (95% CI: 3.9–28.4), thrombosis 4.9% (95% CI: 1.2–8.5), pancreatitis 7.2% (95% CI: 3.1–11.2), bleeding 4.2% (95% CI: −0.5–8.9), cholangitis 4.2% (95% CI: −0.5–8.9), nausea 9.6% (95% CI: 4.4–14.8), biliary obstruction 13.8% (95% CI: 4.2–23.3), chest tightness 7.6% (95% CI: 0.5–14.6), and hypoglycemia 5.9% (95% CI: −0.4–12.2).

Conclusions

This meta-analysis indicated a clear survival benefit for PC patients who received irreversible electroporation therapy, although future safety and effectivity monitoring from more large-scale studies will be needed.

Percutaneous microwave thermosphere ablation of pancreatic tumours

Background

In oncologic field, thermo-ablative procedures have spread more and more. Percutaneous microwave ablation (MWA) showed same benefits and some advantages over radiofrequency ablation (RFA). To date, a disadvantage of both was the not totally predictable size and shape of ablation volume. The aim of this study was to assess feasibility and safety of MWA in nonresectable pancreatic head cancer using a new technology of MW with high power (100 W) and frequency of 2,450 MH.

Methods

Five patients with pancreatic head cancer treated with percutaneous MWA under ultrasound guidance were retrospectively reviewed. Mean lesion diameter was 27.8 mm (range, 25-32 mm). Follow-up was performed by CT after 1, 3, 6 and, when possible, 12 months. The shape of the ablation volume was evaluated with multiplanar reformatting (MPR) using roundness index (RI): a value near 1 represents a more spherical ablation zone shape, and a value distant from 1 implies an oval configuration. Ablation and procedure times were registered, together with hospital stay. The feasibility, safety and quality of life (QoL) were reported.

Results

The procedure was feasible in all patients (100%). A spherical shape of ablation zone was achieved in all cases (mean RI =0.97). Mean ablation and procedure time were respectively of 2.48 and 28 minutes. Mean hospital stay was 4 days. No major complications were observed. Minor complications resolved during the hospital stay. An improvement in QoL was observed in all patients despite a tendency to return to preoperative levels in the months following the procedure.

Conclusions

Percutaneous MWA is a feasible and safe approach for the palliative treatment of advanced stage tumors of the head of the pancreas, despite its complex anatomic relations. The spherical shape of the ablation volume could be related with an improving of the effectiveness and safety.

Intratumoral radiofrequency hyperthermia-enhanced direct chemotherapy of pancreatic cancer

Purpose

To investigate the technical feasibility of using ultrasound-guided intratumoral radiofrequency hyperthermia (RFH) to enhance local chemotherapy of rat orthotopic pancreatic cancers.

Materials and Methods

Orthotopic pancreatic cancer masses were established by inoculating luciferase/mCherry labeled-pancreatic cancer cells into the pancreatic tails of Lewis model rats via a laparotomy approach. Twenty-four rats with pancreatic cancer and 24 mice with subcutaneous pancreatic cancer xenografts in four study groups (n = 6/group) received various treatments: i) combination therapy of intratumoral MR imaging-heating-guidewire-mediated RFH (42^oC) plus local chemotherapy (gemcitabine); ii) intratumoral chemotherapy alone; iii) RFH alone; and (iv)phosphate-buffered saline (PBS). Transcutaneous ultrasound imaging was used to guide the treatment and subsequently follow changes in tumor sizes. Bioluminescence optical imaging was performed to follow photon signal changes. Sonographic and optical findings were correlated with histology at 14 days.

Results

Optical imaging demonstrated a significantly decreased bioluminescence signal in mice with combination therapy group, compared with the other control groups (0.51±0.18 VS 1.6±0.4 VS 3.18±0.9 VS 3.5±0.96, p < 0.05). Ultrasound imaging showed the smallest tumor volumes of both mice and rat group with the combination therapy, compared with other control groups (0.62±0.16 VS 1.25±0.19 VS 2.28±0.25 VS 2.64±0.26, p < 0.05) and (0.75±0.18 VS 1.31±0.30 VS 1.61±0.28 VS 1.72±0.28, p < 0.05). Both imaging findings were confirmed by histologic correlation.

Conclusion

Intratumoral RFH can augment the chemotherapeutic effect in an orthotopic pancreatic cancer model.

Locally Advanced Pancreatic Cancer: A Review of Local Ablative Therapies

Pancreatic cancer is typically characterized by its aggressive tumor growth and dismal prognosis. Approximately 30% of patients with pancreatic cancer present with locally advanced disease, broadly defined as having a tumor-to-artery interface >180°, having an unreconstructable portal vein or superior mesenteric vein and no signs of metastatic disease. These patients are currently designated to palliative systemic chemotherapy, though median overall survival remains poor (approximately 11 months). Therefore, several innovative local therapies have been investigated as new treatment options for locally advanced pancreatic cancer (LAPC). This article provides an overview of available data with regard to morbidity and oncological outcome of novel local therapies for LAPC.

Microwave ablation of pancreatic tumors

OBJECTIVES

To evaluate the clinical performance of percutaneous microwave ablation (MWA) for treatment of locally-advanced-pancreatic-cancer (LAPC).

MATERIAL AND METHODS

Twenty-two MWA sessions (August 2015-March 2017) in 20 patients with primary pancreatic cancer (13 men, 7 women, mean-age: 59.9 ± 8.6 years, range: 46-73 years), who had given informed consent, were retrospectively evaluated. All procedures were performed percutaneously under CT-guidance using the same high-frequency (2.45-GHz) MWA device. Tumor location and diameter, ablation diameter and volume, roundness, duration, technical success and efficacy, output energy, complications, and local tumor progression defined as a tumor focus connected to the edge of a previously technically efficient ablation zone were collected.

RESULTS

Seventeen pancreatic malignant tumors (77.3%) were located in the pancreatic head and five (22.7%) in the pancreatic tail. Initial Mean Tumor Diameter was 30 ± 6 mm. Technical success and efficacy were idem (100%). No major complications occurred. Two patients (9.1%) showed minor complications of severe local pain related to MWA. Post-ablation diameter was on average 34.4 ± 5.8 mm. Mean ablation volume was 7.8 ± 3.8 cm³. The mean transverse roundness index was 0.74 ± 0.14. Mean ablation time was 2.6 ± 0.96 min. The mean applied energy per treatment was 9627 ± 3953 J. Local tumor progression was documented in one case (10%) of the 10/22 available three-month follow-up imaging studies.

CONCLUSION

High-frequency (2.45 GHz) microwave ablation (MWA) for treatment of unresectable and non-metastatic locally-advanced-pancreatic-cancer (LAPC) shows promising results regarding feasibility and safety of percutaneous approach after short-term follow-up and should be further evaluated.

Locally advanced pancreatic cancer: An emerging entity

Pancreatic adenocarcinoma (PDAC) remains a highly fatal disease that is increasing in incidence. PDAC can be classified according to resectability status with 3 nonmetastatic groups defined: resectable, borderline resectable, and locally advanced PDAC (LAPC). Delineating these subtypes is important with the optimal treatment approach dictated by high-quality CT imaging and multidisciplinary team discussion. Patients with LAPC are thought unresectable and are therefore rarely cured. In these patients, chemotherapy remains the mainstay of treatment. Aggressive approaches in this cohort are increasingly employed. Local therapies after induction chemotherapy including standard fractionation radiation, stereotactic body radiotherapy (SBRT), and irreversible electroporation (IRE) are being investigated in an attempt to improve long-term control. In some cases, responses to neoadjuvant therapy may facilitate surgical resection. Biomarkers that can select patients most likely to benefit from these options are urgently needed. This review aims to highlight the emerging treatment of patients with LAPC and to discuss current trials.

Early radiological assessment of locally advanced pancreatic cancer treated with electrochemotherapy

AIM

To report early imaging assessment of ablated area post electrochemotherapy (ECT) in patients with locally advanced pancreatic cancer (LAPC).

METHODS

ECT was performed in 19 LAPC patients enrolled in an approved ongoing clinical phase I/II study. Before and after ECT, 18 patients underwent computed tomography (CT) scan, 11 patients underwent morphological and functional magnetic resonance (MR) scan (dynamic contrast enhanced-MRI) calculating wash-in slope (WIS) and wash-out slope (WOS); diffusion weighted imaging calculating pseudo-diffusivity (Dp), perfusion fraction (fp) and tissue diffusivity (Dt); 10 patients underwent positron emission tomography (PET). Response evaluation criteria in solid tumour (RECIST) on MR and CT were used to assess tumour therapy response. Choi on CT, PET response criteria in solid tumors (PERCIST) on PET and functional parameters on MR were used to evaluate treatment response.

RESULTS

For each patient no significant reduction was measurable by CT and MR using RECIST. According Choi criteria a partial response was obtained in 18/18 (100.0%) patients. According PERCIST criteria 6/10 (60.0%) patients showed a partial response, 3/10 (30.0%) stable disease and 1/10 (10.0%) progression disease. Moreover, using functional MR parameters, a significant reduction of viable tumour after ECT can be observed. According ΔWIS and ΔWOS 9/11 (81.8%) patients exhibited a partial response and 2/11 (18.2%) stable disease; 8/11 (72.7%) patients were considered in partial response by ΔDp evaluation and 3/11 (27.3%) in stable disease; according ΔDt 7/11 (63.6%) patients showed a partial response, 1/11 (9.1%) showed progression of disease and 3/11 (27.3%) were stable. Perfusion fraction fp showed a significant reduction after ECT only in four patients. No significant difference was observed after ECT in signal intensity of T1-weighted images and T2-weighted images, and in equilibrium-phase of contrast study, according to χ² test was observed. A good correlation was reported between ΔHounsfield unit and Δmaximum standardized uptake value and between Δfp and ΔWOS, with a significant statistically difference (P < 0.05) using Spearman correlation coefficient.

CONCLUSION

Perfusion and diffusion MR derived parameters, Choi, PERCIST criteria are more performant than morphological MR and CT criteria to assess ECT treatment response.

Equivalence of cell survival data for radiation dose and thermal dose in ablative treatments: analysis applied to essential tremor thalamotomy by focused ultrasound and gamma knife

Thermal dose and absorbed radiation dose have historically been difficult to compare because different biological mechanisms are at work. Thermal dose denatures proteins and the radiation dose causes DNA damage in order to achieve ablation. The purpose of this paper is to use the proportion of cell survival as a potential common unit by which to measure the biological effect of each procedure. Survival curves for both thermal and radiation doses have been extracted from previously published data for three different cell types. Fits of these curves were used to convert both thermal and radiation dose into the same quantified biological effect: fraction of surviving cells. They have also been used to generate and compare survival profiles from the only indication for which clinical data are available for both focused ultrasound (FUS) thermal ablation and radiation ablation: essential tremor thalamotomy. All cell types could be fitted with coefficients of determination greater than 0.992. As an illustration, survival profiles of clinical thalamotomies performed by radiosurgery and FUS are plotted on a same graph for the same metric: fraction of surviving cells. FUS and Gamma Knife have the potential to be used in combination to deliver a more effective treatment (for example, FUS may be used to debulk the main tumour mass, and radiation to treat the surrounding tumour bed). In this case, a model which compares thermal and radiation treatments is valuable in order to adjust the dose between the two.

Multi-modality imaging-monitored creation of rat orthotopic pancreatic head cancer with obstructive jaundice

Purpose

To investigate the feasibility of using multi-modality imaging to monitor the creation of rat models with orthotopic pancreatic head cancer with obstructive jaundice.

Results

27 of 52 rats (51.92%) developed pancreatic head cancer. The tumor formation rate was significantly higher in the animal group receiving bioluminescent tumor, compared to the group receiving non-bioluminescent donor tumors [78.1% (25/32 rats) vs 10.0% (2/20 rats), P = 0.0001]. Both ultrasound imaging and MRI clearly characterized the orthotopic tumors. Laboratory biochemistry test for those rats with obstructive jaundice showed elevated levels of bilirubin, aspartate transaminase (AST), alkaline phosphatase (ALT) and gamma-glutamyl transpeptidase (λ-GGT), compared with those rats without jaundice (P < 0.05). Correlative pathology confirmed that all tumors were ductal adenocarcinomas, and located in pancreatic head regions.

Materials and Methods

Rat pancreatic adenocarcinoma cells (DSL-6A/C1) were first transfected with lentivirus/mCherry-luciferase genes, and then subcutaneously implanted into flanks of donor immunocompetent Lewis rats, to create pancreatic tumor tissues. The tumor tissues from donor rats with either bioluminescence signal or without the signal were then transplanted into the pancreatic heads of 52 recipient Lewis rats. Bioluminescence optical and ultrasound imaging, as well as magnetic resonance imaging (MRI), were performed to follow up the tumor formation and growth in these tumor-transplanted rats. Physical examination and biochemistry test were used to discern the rats with obstructive jaundice. The rats were euthanized for subsequent histologic correlation and confirmation.

Conclusions

We successfully created a new rat model with orthotopic pancreatic head cancer, which can be accurately monitored and visualized by different imaging modalities.

Percutaneous ablation of pancreatic cancer

Pancreatic ductal adenocarcinoma is a highly aggressive tumor with an overall 5-year survival rate of less than 5%. Prognosis and treatment depend on whether the tumor is resectable or not, which mostly depends on how quickly the diagnosis is made. Chemotherapy and radiotherapy can be both used in cases of non-resectable pancreatic cancer. In cases of pancreatic neoplasm that is locally advanced, non-resectable, but non-metastatic, it is possible to apply percutaneous treatments that are able to induce tumor cytoreduction. The aim of this article will be to describe the multiple currently available treatment techniques (radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation), their results, and their possible complications, with the aid of a literature review.

Ablation Strategies for Locally Advanced Pancreatic Cancer

With the advent of novel and somewhat effective chemotherapy against pancreas cancer, several groups developed a new interest on locally advanced pancreatic cancer (LAPC). Unresectable tumors constitute up to 80% of pancreatic cancer (PC) at the time of diagnosis and are associated with a 5-year overall survival of less than 5%. To control those tumors locally, with perhaps improved patients survival, significant advances were made over the last 2 decades in the development of ablation methods including cryoablation, radiofrequency ablation, microwave ablation, high intensity focused ultrasound and irreversible electroporation (IRE). Many suggested a call for caution for possible severe or lethal complications in using such techniques on the pancreas. Most fears were on the heating or freezing of the pancreas, while non-thermal ablation (IRE) could offer safer approaches. The multimodal therapies along with high-resolution imaging guidance have created some enthusiasm toward ablation for LAPC. The impact of ablation techniques on primarily non-resectable PC remains, however, unclear.

Temperature feedback-controlled photothermal treatment with diffusing applicator: theoretical and experimental evaluations

To minimize thermal injury, the current study evaluated the real-time temperature monitoring with a proportional-integrative-derivative (PID) controller during 980-nm photothermal treatment with a radially-diffusing applicator. Both simulations and experiments demonstrated comparable thermal behaviors in temperature distribution and the degree of irreversible tissue denaturation. The PID-controlled application constantly maintained the pre-determined temperature of 353 K (steady-state error = < 1 K). Due to constant energy delivery, coagulation volumes linearly increased up to 1.04 ± 0.02 cm(3) with irradiation time. Integration of temperature feedback with diffuser-assisted photothermal treatments can provide a feasible therapeutic modality to treat pancreatic tumors in an effective manner.

Current therapeutic strategies for advanced pancreatic cancer: A review for clinicians

Pancreatic cancer (PC) would become the second leading cause of cancer death in the near future, despite representing only 3% of new cancer diagnosis. Survival improvement will come from a better knowledge of risk factors, earlier diagnosis, better integration of locoregional and systemic therapies, as well as the development of more efficacious drugs rising from a deeper understanding of disease biology. For patients with unresectable, non-metastatic disease, combined strategies encompassing primary chemotherapy and radiation seems to be promising. In fit patients, new polychemotherapy regimens can lead to better outcomes in terms of slight but significant survival improvement associated with a positive impact on quality of life. The upfront use of these regimes can also increase the rate of radical resections in borderline resectable and locally advanced PC. Second line treatments showed to positively affect both overall survival and quality of life in fit patients affected by metastatic disease. At present, oxaliplatin-based regimens are the most extensively studied. Nonetheless, other promising drugs are currently under evaluation. Presently, in addition to surgery and conventional radiation therapy, new locoregional treatment techniques are emerging as alternative options in the multimodal approach to patients or diseases not suitable for radical surgery. As of today, in contrast with other types of cancer, targeted therapies failed to show relevant activity either alone or in combination with chemotherapy and, thus, current clinical practice does not include them. Up to now, despite the fact of extremely promising results in different tumors, also immunotherapy is not in the actual therapeutic armamentarium for PC. In the present paper, we provide a comprehensive review of the current state of the art of clinical practice and research in PC aiming to offer a guide for clinicians on the most relevant topics in the management of this disease.

CT Findings of Patients Treated with Irreversible Electroporation for Locally Advanced Pancreatic Cancer

Introduction. In patients with locally advanced pancreatic cancer (LAPC), IRE has been shown to be safe for local disease control and palliation. As IRE continues to gain acceptance it is important to characterize the expected imaging findings. Materials and Methods. A review of our prospective soft tissue ablation registry from July 2010 to June 2013 was performed on patients who had undergone IRE for LAPC. Five masses treated with intraoperative IRE ablation for pancreatic tumors that underwent CT imaging before and after ablation were reviewed. Results and Discussion. Following IRE, the postablation bed is larger than the original ablated tumor. This ablation zone may get smaller in size (due to decreased edema and hyperemia) in the following months and more importantly remains stable provided there is no recurrence. In cases of recurrent disease there is increased size of the ablation bed, mass effect, and new or worsening vascular encasement or occlusion. Conclusion. CT imaging remains the best current imaging modality to assess post-IRE ablation changes. Serial imaging over at least 2-6 months must be employed to detect recurrence by comparing with prior studies in conjunction with clinical and serum studies. Larger imaging studies are underway to evaluate a more ideal imaging modality for this unique patient population.

Pancreatic cancer: current management and treatment strategies

The 5-year survival of patients with pancreatic cancer is poor and, despite oncological advances over the past two decades, has not significantly improved. However, there have been several surgical and oncological advances which have improved morbidity and mortality in surgery and more efficacious chemotherapy regimens, resulting in a better patient experience and an increase in survival by a number of months. Most patients have a tumour at the head of the pancreas and those with resectable disease undergo a pancreaticoduodenectomy, which can be performed laparoscopically. Those who have a pancreatic resection have an increased survival in comparison with those receiving oncological treatment only; however, only a quarter of patients have resectable disease at diagnosis. Some centres are now performing venous resections and/or arterial resections in order to increase the number of patients eligible for curative surgery. Innovative techniques using ablation technologies to downstage tumours for resection are also being investigated. After surgery, all patients should be offered adjuvant gemcitabine-based chemotherapy. Those with locally advanced tumours not suitable for surgery should be offered FOLFIRINOX chemotherapy, after which the tumour may be suitable for surgical resection. The use of radiotherapy in this group of patients is controversial but offered by a few centres. Patients with metastatic disease at diagnosis should also be offered FOLFIRINOX chemotherapy, which can improve survival by a few months. As our knowledge of the tumour biology of pancreatic cancer progresses, a number of new agents targeting specific genes and proteins are under investigation and there is hope that median survival will continue to improve over the next decade.

Percutaneous Microwave Ablation of an Insulinoma in a Patient with Refractory Symptomatic Hypoglycemia

Insulinomas are the most common functioning pancreatic neuroendocrine tumors (pNETs). Surgical excision is the preferred therapy, and medical treatment with diazoxide or octreotide is typically reserved for those who are poor surgical candidates. A recent emergence of minimally invasive treatment modalities has led to reports of successful radiofrequency and ethanol ablation of insulinomas. We report the first use of microwave ablation for treatment of an insulinoma in a patient with medical comorbidities contraindicating surgery.

Irreversible electroporation of the pancreas is feasible and safe in a porcine survival model

OBJECTIVES

Use of thermal tumor ablation in the pancreatic parenchyma is limited because of the risk of pancreatitis, pancreatic fistula, or hemorrhage. This study aimed to evaluate the feasibility and safety of irreversible electroporation (IRE) in a porcine model.

METHODS

Ten pigs were divided into 2 study groups. In the first group, animals received IRE of the pancreatic tail and were killed after 60 minutes. In the second group, animals received IRE at the head of the pancreas and were followed up for 7 days. Clinical parameters, computed tomography imaging, laboratory results, and histology were obtained.

RESULTS

All animals survived IRE ablation, and no cardiac adverse effects were noted. Sixty minutes after IRE, a hypodense lesion on computed tomography imaging indicated the ablation zone. None of the animals developed clinical signs of acute pancreatitis. Only small amounts of ascites fluid, with a transient increase in amylase and lipase levels, were observed, indicating that no pancreatic fistula occurred.

CONCLUSIONS

This porcine model shows that IRE is feasible and safe in the pancreatic parenchyma. Computed tomography imaging reveals significant changes at 60 minutes after IRE and therefore might serve as an early indicator of therapeutic success. Clinical studies are needed to evaluate the efficacy of IRE in pancreatic cancer.

Electrochemotherapy in locally advanced pancreatic cancer: Preliminary results

OBJECTIVE

Report the preliminary results on electrochemotherapy (ECT) in the treatment of locally advanced pancreatic cancer of a phase I/II study and described the new functional imaging tools to assess ECT response in Magnetic Resonance (MR) imaging compared to morphological Computer Tomography (CT), ultrasound (US) without and with contrast enhancement (CEUS) and MR Imaging.

MATERIALS AND METHODS

Thirteen patients were enrolled in an ongoing clinical phase I/II study approved by Ethical Committee of National Cancer Institute G. Pascale Foundation - IRCCS of Naples. ECT with bleomycin was performed during open surgery. All patients underwent US and CT scan, before and after ECT treatment; 7 patients were evaluated using morphological and functional (dynamic contrast enhancement-DCE and diffusion weighted- DW) parameters in MR; 5 patients underwent CEUS. RECIST criteria were used to evaluate ECT response on US, CT and MR images. Functional parameters were also used to evaluate ECT response on MR images.

RESULTS

No acute (intraoperative) and/or postoperative serious adverse events related to electrochemotherapy were observed; no clinically significant electrocardiographic, hemodynamic, or serum biologic changes were noted. No clinically relevant elevation of amylase or lipase levels was observed and no bleeding or damage to surrounding viscera occurred. In three patients had seen splenic infarction without thrombosis of the splenic vessels.

CONCLUSION

Electrochemotherapy is feasible and safe treatment modality in patients with locally advanced pancreatic adenocarcinoma. Dynamic and diffusion MR imaging in comparison to MR morphological sequence alone and to UC and CT imaging is more suitable to assess ECT treatment response. CEUS is not indicated in follow up after ECT.