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

Evaluation of cryoablation using a prototype cryoablation needle in swine liver

BACKGROUND/AIMS

Pancreatic cancer poses significant challenges due to its tendency for late-stage diagnosis and high mortality rates. Cryoablation, a technique used to treat various types of cancer, has shown potential in enhancing the prognosis of pancreatic cancer when combined with other therapies. However, its implementation is often limited by the need for lengthy procedures and specialized equipment. This study aims to develop a cryoablation needle optimized for endoscopic ultrasonography to simplify its application in treating pancreatic cancer.

METHODS

The study involved conducting cryoablation experiments on swine liver tissue. It utilized cryo-needles to evaluate the extent of cell death across various temperatures and durations of cryoablation.

RESULTS

The cryoablation system, which employed liquid carbon dioxide, achieved rapid cooling, reaching temperatures below -60 °C within 30 seconds and maintained the cryoablation process for 200 seconds. These conditions resulted in necrosis of the liver tissue. Notable cellular changes were observed up to 15 mm away from the cryoablation needle.

CONCLUSIONS

This experimental study successfully demonstrated the efficacy of using a cryo-needle for cryoablation in swine liver tissue. Further trials involving pancreatic tissue are expected to verify its effectiveness, underscoring the importance of continued research to establish its role as a complementary therapy in pancreatic cancer treatment.

Perioperative outcomes and long-term survival of cryosurgery on unresectable pancreatic cancer: a systematic review and meta-analysis

BACKGROUND

Pancreatic cancer (PC) continues to rank as one of the deadliest forms of cancer, with the majority of patients being diagnosed with unresectable disease. The implementation of cryoablation-based comprehensive treatment is expected to lead to a reduction in tumour size and potentially achieve complete resection. However, the availability of systematic and evidence-based treatment guidelines for cryoablation in pancreatic cancer is currently limited.

MATERIALS AND METHODS

A computerized search was conducted in the Medline, Embase, Cochrane Library databases, and Clinicaltrials to retrieve studies published from August 1987 to June 2023. The perioperative outcomes and long-term survival of patients with locally advanced pancreatic cancer (LAPC) or metastatic pancreatic cancer (mPC) who underwent cryosurgery were systematically collected. Heterogeneity was assessed using Cochran's Q test, and a funnel plot was implemented to evaluate publication bias. Data were pooled and analyzed using Stata 14.0 software. The Newcastle-Ottawa Quality Assessment Form tool was employed for quality evaluation.

RESULTS

Nine studies, including 368 patients, were identified. The pooled overall incidence rate was 4% (95% CI: 0-14%; I²=54.06%) for acute pancreatitis, 0% (95% CI: 0-0%; I²=0.0%) for delayed gastric emptying, 0% (95% CI: 0-1%; I²=0.0%) for postoperative pancreatic fistula (POPF) or bile leakage, 2% (95% CI: 0-5%; I²=0.0%) for bleeding, and 4% (95% CI: 0-12%; I²=70.46%) for fever. The subgroup analysis revealed that the percutaneous treatment group had a lower incidence of complications compared to laparotomy but had higher incidences of POPF, bleeding, and pancreatitis than the intraoperative group. Median overall survival (OS) varied from 5 to 16.2 months. The median survival rates at 6, 12, 24, and 36 months for patients who underwent cryosurgery were as follows: 94.9%, 64.8% (range: 4.8-63.1%), 22.80%, and 9.5%, respectively.

CONCLUSION

With the advancements in cryoablation and anti-tumour therapy, cryoablation has emerged as a promising treatment modality for patients with unresectable pancreatic cancer. According to existing literature, the combination of cryoablation with radioactive particle implantation or immunotherapy has demonstrated considerable efficacy and safety. However, while the majority of included data is derived from retrospective studies, it is imperative to conduct larger sample sizes or prospective trials for further validation.

Pancreatic Cancer: Challenges and Opportunities in Locoregional Therapies

Simple Summary

Pancreatic cancer is a serious ongoing global health burden, with an overall 5-year survival rate of less than 5%. One major hurdle in the treatment of this disease is the predominantly elderly patient population, leading to their ineligibility for curative surgery and a low rate of successful outcomes. Systemic administration introduces chemo-agents throughout the body via the blood, attacking not only tumours but also healthy organs. When localised interventions are employed, chemo-agents are retained specifically at tumour site, minimizing unwanted toxicity. As a result, there is a growing interest in finding novel localised interventions as alternatives to systemic therapy. Here, we present a detailed review of current locoregional therapies used in pancreatic cancer therapy. This work aims to present a thorough guide for researchers and clinicians intended to employ established and novel localised interventions in the treatment of pancreatic cancer. Furthermore, we present our insights and opinions on the potential ideals to improve these tools.

Abstract

Pancreatic cancer (PC) remains the seventh leading cause of cancer-related deaths worldwide and the third in the United States, making it one of the most lethal solid malignancies. Unfortunately, the symptoms of this disease are not very apparent despite an increasing incidence rate. Therefore, at the time of diagnosis, 45% of patients have already developed metastatic tumours. Due to the aggressive nature of the pancreatic tumours, local interventions are required in addition to first-line treatments. Locoregional interventions affect a specific area of the pancreas to minimize local tumour recurrence and reduce the side effects on surrounding healthy tissues. However, compared to the number of new studies on systemic therapy, very little research has been conducted on localised interventions for PC. To address this unbalanced focus and to shed light on the tremendous potentials of locoregional therapies, this work will provide a detailed discussion of various localised treatment strategies. Most importantly, to the best of our knowledge, the aspect of localised drug delivery systems used in PC was unprecedentedly discussed in this work. This review is meant for researchers and clinicians considering utilizing local therapy for the effective treatment of PC, providing a thorough guide on recent advancements in research and clinical trials toward locoregional interventions, together with the authors’ insight into their potential improvements.

Image-guided locoregional non-intravascular interventional treatments for hepatocellular carcinoma: Current status

Hepatocellular carcinoma (HCC) is one of the most deadly and frequent cancers worldwide, although great advancement in the treatment of this malignancy have been made within the past few decades. It continues to be a major health issue due to an increasing incidence and a poor prognosis. The majority of patients have their HCC diagnosed at an intermediate or advanced stage in theUSA or China. Curative therapy such as surgical resection or liver transplantation is not considered anoption of treatment at these stages.

Transarterial chemoembolization (TACE), the most widely used locoregional therapeutic approach, used to be the mainstay of treatment for cases with unresectable cancer entities. However, for those patients with hypovascular tumors or impaired liver function reserve, TACE is a suboptimal treatment option. For example, embolization does not result in complete coverage of a hypovascular tumor, and may rather promotes postoperative tumor recurrence, or leave residual tumor, in these TACE-resistance patients. In addition, TACE carries a higher risk of hepatic decompensation in patients with poor liver function or reserve.

Non-vascular interventional locoregional therapies for HCC include radiofrequency ablation (RFA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), laser-induced thermotherapy (LITT), cryosurgical ablation (CSA), irreversible Electroporation (IRE), percutaneous ethanol injection (PEI), and brachytherapy. Recent advancements in these techniques have significantly improved the treatment efficacy of HCC and expanded the population of patients who qualify for treatment. This review embraces the current status of imaging-guided locoregional non-intravascular interventional treatments for HCCs, with a primary focus on the clinical evaluation and assessment of the efficacy of combined therapies using these interventional techniques.

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.

Cryoimmunology: Opportunities and challenges in biomedical science and practice

Autologous and allogeneic cryoimmunological medicine is a brand new branch of biomedical science and clinical practice that examines the features and formation of the immune response to immunogenic properties of normal and malignant biological structures altered by ultralow temperature, as well as specific changes in the structural and functional characteristics of immune cells and tissues after cryopreservation. Cryogenic protein denaturation phenomenon provides important insights into the mechanisms underlying the damage to cryogenic lesions immediately after freeze-thawing sessions in bioscience and medicine applications. The newly formed cryocoagulated protein components (cryomodified protein components) are crucial in cryoimmunology from the perspective of the formation of immunological substances at ultralow temperatures. Dendritic cells and cryocell detritus (cryocell debris) formed in living biological tissue after exposure to ultralow temperature in vivo may be an indication of one of the essential mechanisms involved in the cryoimmunological response of living structures to the impact of ultralow temperature exposure. Hence, the formation of new autologous and allogeneic cryoinduced immunogenic substances is a novel concept in biomedical research globally. Accordingly, this review focuses on issues concerning the peculiarities of the interaction of the immune system with a dominant malignant neoplasm tissue after exposure to subzero temperatures, considering the original cryogenic technical approaches. We present an overview of the state-of-the-art methods of cryoimmunology, and their major developments, past and present. The need for the delineation of structural and functional characteristics of the biological substrates of the immune system after cryopreservation that can be used in adoptive cell therapy, especially in cancer patients, is emphasized.

Acute Phase Response and Postprocedural Evaluation of Open and Laparoscopic Cryoablation Procedures in Porcine Pancreases

OBJECTIVES

Cryoablation is a potentially less invasive locoregional ablation modality. Although cryoablation has been used to treat malignancy in various organs, a limited application of this modality in the pancreas has been reported.

METHODS

Acute phase response assessments and postprocedural course evaluations of 2 experimental locoregional ablation methods were conducted. In one method, open and laparoscopic cryoablation of a porcine pancreas using an argon-helium gas-based cryoablation system and monitoring of tissue temperature during the procedure were performed. In the other method, open cryoablation of a porcine pancreas using liquid nitrogen was performed. The animals were evaluated postoperatively.

RESULTS

The size of the cryolesion was larger in the second treatment than in the first. Laparoscopic cryoablation was associated with the formation of an iceball, which possibly affected the surrounding structures. The ablated region was adequately cooled with 10 minutes of freeze/repeat cycles. The area cooled to a temperature of less than -40°C was approximately half the size of the cryolesion in diameter. The swine used for the evaluation of the postprocedural course survived 3 weeks after the procedure with a temporal elevation of the serum lipase level.

CONCLUSIONS

Cryoablation of the pancreas was experimentally practicable without severe complications under direct or laparoscopic vision.

A review on the efficacy and safety of iodine-125 seed implantation in unresectable pancreatic cancers

Background: Pancreatic cancers are the common digestive system tumors with poor prognosis and due to its late diagnosis, surgical resection does not remain a viable treatment option in about 80% of patients. Amongst different treatment options, radioactive 125I seed implantation therapy has also emerged as a good alternative in non-resectable pancreatic cancer patients.Purpose: The present review describes the efficacy and safety of iodine-125 seed implantation in unresectable pancreatic cancers in preclinical and clinical studies.Results: In this technique, small radioactive particles are implanted inside the tumor cells to produce the sustain effects. Due to the short radial distance of these radiations, there is a selective and efficient killing of cancer cells without any significant injury to the neighboring cells. Amongst the different methods for implanting 125I seeds in the pancreatic tissues, CT scan or ultrasound-guided percutaneous seed implantation is preferred as it offers shorter operative time, lesser bleeding, early recovery, lesser complications, and low medical costs. The clinical studies have shown that radioactive 125I seed implantation is a good option for the management of local tumor growth, pain palliation, and improvement in the life span of patients suffering from unresectable pancreatic cancer.Conclusion: It may be employed either alone or in combination with cryotherapy, existing chemotherapy, bypass surgery or radiations to achieve the optimal results in these patients. Nevertheless, there is a need to formulate a uniform dose and procedure to achieve homogeneity and develop references for clinical practices.

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.