Percutaneous ultrasonography and computed tomography guided pancreatic cryoablation: feasibility and safety assessment

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.

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.

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.

Immunotherapy Plus Cryotherapy: Potential Augmented Abscopal Effect for Advanced Cancers

Since the 1920s the gold standard for treating cancer has been surgery, which is typically preceded or followed with chemotherapy and/or radiation, a process that perhaps contributes to the destruction of a patient’s immune defense system. Cryosurgery ablation of a solid tumor is mechanistically similar to a vaccination where hundreds of unique antigens from a heterogeneous population of tumor cells derived from the invading cancer are released. However, releasing tumor-derived self-antigens into circulation may not be sufficient enough to overcome the checkpoint escape mechanisms some cancers have evolved to avoid immune responses. The potentiated immune response caused by blocking tumor checkpoints designed to prevent programmed cell death may be the optimal treatment method for the immune system to recognize these new circulating cryoablated self-antigens. Preclinical and clinical evidence exists for the complementary roles for Cytotoxic T-lymphocyte-associated protein (CTLA-4) and PD-1 antagonists in regulating adaptive immunity, demonstrating that combination immunotherapy followed by cryosurgery provides a more targeted immune response to distant lesions, a phenomenon known as the abscopal effect. We propose that when the host’s immune system has been “primed” with combined anti-CTLA-4 and anti-PD-1 adjuvants prior to cryosurgery, the preserved cryoablated tumor antigens will be presented and processed by the host’s immune system resulting in a robust cytotoxic CD8⁺ T-cell response. Based on recent investigations and well-described biochemical mechanisms presented herein, a polyvalent autoinoculation of many tumor-specific antigens, derived from a heterogeneous population of tumor cancer cells, would present to an unhindered yet pre-sensitized immune system yielding a superior advantage in locating, recognizing, and destroying tumor cells throughout the body.

Clinical Practice Guidelines for Cryosurgery of Pancreatic Cancer: A Consensus Statement From the China Cooperative Group of Cryosurgery on Pancreatic Cancer, International Society of Cryosurgery, and Asian Society of Cryosurgery

Pancreatic cancer (PC), one of the most lethal malignancies, accounts for 8% to 10% of digestive system cancers, and the incidence is increasing. Surgery, chemotherapy, and radiotherapy have been the main treatment methods but are not very effective. Cryosurgery was first used in 1984 for treatment of locally advanced PC and has since become a considerable treatment for most cases of unresectable PC. During the past decade, cryosurgery has been applied in some hospitals in China, and the newly developed technique of computed tomography- and/or ultrasound-guided percutaneous cryosurgery has shown better results than chemotherapy in cases of unresectable locally advanced PC, with the 1-year survival rate reported to be more than 50%. To develop standardized criteria for the application of cryosurgery in PC, the International Society of Cryosurgery and Asian Society of Cryosurgery assembled experts from Austria, Japan, and China to discuss treatment methods and arrive at a consensus on the indications, contraindications, and preferred techniques of PC cryosurgery.

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.

Use of cryoablation beyond the prostate

Cryoablation has been used for many years as a surgical ablation technique in the prostate and kidney. However, since the introduction of high-intensity focused ultrasound (HIFU) and robotic surgery for prostate tumours, its popularity in the urologic community has declined. In the early 2000s, innovations in cryoablation technology allowed the use of thinner probes, which were suitable for percutaneous application. As a result, radiologists began using cryoablation, first in the liver, and then in other organs or tissues such as the kidney, lung, breast, pancreas, bone, and soft tissue. In most of these locations, cryoablation has great potential given its inherent advantages, including the use of local anaesthesia, little or no pain during and after the procedure, real-time monitoring of the ablation area on US, CT or MRI, the potential for ablation of large tumours with multiple probes, and the ability to change the shape of the ablation in non-spherical tumours. Yet despite these advantages, the use of percutaneous cryoablation among radiologists appears to be far lower than that of heat-based ablation techniques. The aim of this article is to outline specific aspects of cryoablation and to illustrate its potential clinical applications with case presentations.

KEY POINTS

• Recent advances have made cryoablation suitable for percutaneous use by radiologists with image guidance. • Cryoablation has distinct advantages over heat-based ablation techniques. • Cryoablation is becoming increasingly popular for lung, breast, kidney, bone, and soft tissue tumours.

Advances in cryoablation for pancreatic cancer

Pancreatic carcinoma is a common cancer of the digestive system with a poor prognosis. It is characterized by insidious onset, rapid progression, a high degree of malignancy and early metastasis. At present, radical surgery is considered the only curative option for treatment, however, the majority of patients with pancreatic cancer are diagnosed too late to undergo surgery. The sensitivity of pancreatic cancer to chemotherapy or radiotherapy is also poor. As a result, there is no standard treatment for patients with advanced pancreatic cancer. Cryoablation is generally considered to be an effective palliative treatment for pancreatic cancer. It has the advantages of minimal invasion and improved targeting, and is potentially safe with less pain to the patients. It is especially suitable in patients with unresectable pancreatic cancer. However, our initial findings suggest that cryotherapy combined with 125-iodine seed implantation, immunotherapy or various other treatments for advanced pancreatic cancer can improve survival in patients with unresectable or metastatic pancreatic cancer. Although these findings require further in-depth study, the initial results are encouraging. This paper reviews the safety and efficacy of cryoablation, including combined approaches, in the treatment of pancreatic cancer.

Alleviating visceral cancer pain in patients with pancreatic cancer using cryoablation and celiac plexus block

Little is known about the effects of pancreas cryoablation (PCA) on abdominalgia in pancreatic cancer patients or its synergism with celiac plexus block (CPB). In patients without abdominalgia, to investigate the effects of PCA; in patients with abdominalgia, to investigate the pain-alleviating effects of PCA+CPB. Sixty-two patients were enrolled in this retrospective review; 12 without abdominalgia refused PCA, 15 without abdominalgia received PCA to reduce their tumor load and 35 with abdominalgia received PCA+CPB to reduce tumor load and alleviate pain. All PCA and PCA+CPB procedures were performed successfully. Some slight adverse effects (e.g. increased serum amylase, abdominal distension and nausea, abdominal bleeding) had disappeared by 3weeks, spontaneously or after symptomatic treatment. In patients without abdominalgia, pain occurred in one-third of cases (all with pancreatic head cancer) after PCA but had stopped 1-12days after treatment; in patients with abdominalgia before treatment, pain stopped immediately after PCA+CPB in 18 cases and 2-24days after treatment in 17 (all with pancreatic head cancer); a significant difference was found between pretreatment and post-treatment pain frequency (P=0.0019), regardless of the presence of advanced (P=0.0096) or metastatic (P=0.0072) cancer. The average time to pain relief was approximately 7days after both PCA and PCA+CPB, and abdominalgia did not recur for more than 8weeks. PCA may cause short-term pain in some pancreatic cancer patients. Combined PCA+CPB can alleviate cancer pain for more than 8weeks, without severe side effects.