The efficacy and safety of the open approach irreversible electroporation in the treatment of pancreatic cancer: A systematic review

Papel da imagem na indicação da eletroporação irreversível no manejo terapêutico do adenocarcinoma de pâncreas

Resumo O adenocarcinoma ductal de pâncreas é uma das neoplasias malignas mais agressivas, com taxas de sobrevivência anuais inferiores a 20%. Os métodos axiais (tomografia computadorizada e ressonância magnética) têm papel fundamental no diagnóstico e estadiamento da doença, por fornecerem adequada resolução anatômica na avaliação de estruturas-chave, principalmente vasculares. O adenocarcinoma ductal de pâncreas é frequentemente descoberto em estágios avançados e sem viabilidade de ressecção cirúrgica, e nesse cenário o desenvolvimento de alternativas terapêuticas minimamente invasivas tem sido ainda mais importante para a mudança de sua história natural. A eletroporação irreversível, procedimento intervencionista que minimiza efeitos deletérios nos tecidos adjacentes, vem se destacando no tratamento de lesões tradicionalmente consideradas irressecáveis. Essa técnica, apesar de ganhar cada vez mais espaço no manejo terapêutico do adenocarcinoma ductal de pâncreas, ainda é pouco familiar aos radiologistas. Neste estudo, buscamos expor, de forma sucinta e didática, os fundamentos da técnica, as principais características de imagem e os critérios de elegibilidade que devem ser considerados para indicação da eletroporação irreversível nessa doença.

Role of imaging in the applicability of irreversible electroporation for the management of pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma is one of the most aggressive malignant neoplasms, with a one-year survival rate below 20%. Axial methods (computed tomography and magnetic resonance imaging) play a fundamental role in the diagnosis and staging of the disease, because they provide adequate anatomical resolution in the assessment of key structures, mainly vascular structures. Pancreatic ductal adenocarcinoma is most often discovered in advanced stages, when surgical resection is no longer feasible. In that scenario, minimally invasive treatment alternatives have been developed in attempts to change the natural history of the disease. Irreversible electroporation, an interventional procedure that minimizes deleterious effects on adjacent tissues, has proven useful for the treatment of tumors traditionally considered unresectable. Despite the growing acknowledgment of this technique as a tool for the management of pancreatic ductal adenocarcinoma, it is still relatively unknown among radiologists. In this study, we sought to provide an overview of the main characteristics and eligibility criteria that must be considered for the indication of irreversible electroporation in cases of pancreatic ductal adenocarcinoma.

Long-term follow-up experience with adjuvant therapy after irreversible electroporation of locally advanced pancreatic cancer

BACKGROUND

Irreversible electroporation (IRE) expands the surgical options for patients with unresectable pancreatic cancer. This study evaluated for differences in survival stratified by type of IRE and receipt of adjuvant chemotherapy.

METHODS

Patients with locally advanced pancreatic cancer treated by IRE (2012-2020) were retrospectively included. Overall survival (OS) and recurrence-free survival (RFS) were compared by type of IRE (in situ for local tumor control or IRE of potentially positive margins with resection) and by receipt of adjuvant chemotherapy.

RESULTS

Thirty-nine patients had IRE in situ, 61 had IRE for margin extension, and 19 received adjuvant chemotherapy. Most (97.00%) underwent induction chemotherapy. OS was 28.71 months (interquartile range [IQR] 19.17, 51.19) from diagnosis, with no difference by IRE type (hazard ratio [HR] 1.05 for margin extension [p = 0.85]) or adjuvant chemotherapy (HR 1.14 [p = 0.639]). RFS was 8.51 months (IQR 4.95, 20.17) with no difference by IRE type (HR 0.90 for margin extension [p = 0.694]) or adjuvant chemotherapy (HR 0.90 [p = 0.711]).

CONCLUSION

These findings suggest that adjuvant therapy may have limited benefit for patients treated with induction chemotherapy followed by local control with IRE for unresectable pancreatic cancer. Further study of the duration and timing of systemic therapy is warranted to maximize benefit and limit toxicity.

The Synergistic Role of Irreversible Electroporation and Chemotherapy for Locally Advanced Pancreatic Cancer

Irreversible electroporation (IRE) is a local ablative technique used in conjunction with chemotherapy to treat locally advanced pancreatic cancer (LAPC). The combination of IRE and chemotherapy has showed increased overall survival when compared to chemotherapy alone, pointing towards a possible facilitating effect of IRE on chemotherapeutic drug action and delivery. This review aims to present current chemotherapeutic regimens for LAPC and their co-implementation with IRE, with an emphasis on possible molecular augmentative mechanisms of drug delivery and action. Moreover, the potentiating mechanism of IRE on immunotherapy, M1 oncolytic virus and dendritic cell (DC)-based treatments is briefly explored. Investigating the synergistic effect of IRE on currently established treatment regimens as well as newer ones, may present exciting new possibilities for future studies seeking to improve current LAPC treatment algorithms.

Irreversible Electroporation (IRE) Combined With Chemotherapy Increases Survival in Locally Advanced Pancreatic Cancer (LAPC)

OBJECTIVES

Locally advanced pancreatic cancer (LAPC) is found in about 40% of patients with pancreatic cancer. Irreversible electroporation (IRE) is a nonthermal ablative technique that provides an alternative in patients with LAPC and can be safely combined with chemotherapy.

MATERIALS AND METHODS

From 2015 until October of 2019, we performed laparotomic IRE in a total of 40 patients with stage III LAPC. The median age of these patients was 65.2 years (range: 46 to 81 y), and the median tumor size was 3.8 cm (range: 2 to 5.2 cm). 33 of 40 patients were treated preoperatively with FOLFIRINOX or nab-paclitaxel plus gemcitabine and in case of disease control, IRE was performed, whereas in 7 patients, IRE was performed without previous chemotherapy.

RESULTS

All patients were treated successfully with IRE as the tumor evaluation showed no disease progression after the completion of induction chemotherapy. No IRE-related deaths occurred. Two major grade III complications were reported: pancreatic fistula grade A in 8 patients and 3 patients diagnosed with delayed gastric emptying. Up to October 31, 2019, the median overall survival (OS) of all patients was 24.2 months (range: 6 to 36 mo), and the median progression-free survival was 10.3 months (range: 3 to 24 mo). After the completion of IRE, 30 patients (75%) continued with adjuvant chemotherapy. Fifteen patients (37%) have >24 months OS and 3 patients (8%) have reached 36 months OS and are still alive.

CONCLUSION

The combination of chemotherapy with IRE, which is a safe and effective procedure, may result in a survival benefit for patients with LAPC.

A Thought-Provoking Case of Successfully Treated Carcinoma of the Head of the Pancreas with Metachronous Lung Metastasis: Impact of Distal Spleno-Renal Shunt for Regional Invasion on Long-Term Period after Pancreaticoduodenectomy

When performing pancreaticoduodenectomy with resection of the confluence of the superior mesenteric vein and portal vein, division of the splenic vein may cause sinistral portal hypertension resulting in gastrointestinal bleeding, splenic congestion, and hypersplenism. To prevent these adverse events, it is important to intentionally decompress the splenic vein. This report is of a 68-year-old woman with stage IA carcinoma of the head of the pancreas who survived for more than six years following tumor resection and pancreaticoduodenectomy and distal splenorenal shunt. A 68-year-old woman was diagnosed with carcinoma of the head of the pancreas that involved the confluence of the superior mesenteric vein, portal vein, and splenic vein. No unresectable cancer sites or distant metastases were detected. Pancreaticoduodenectomy with resection of the confluence of the superior mesenteric vein and portal vein was performed. The superior mesenteric vein and portal vein were anastomosed in the end-to-end fashion, and the remnant splenic vein was anastomosed to the superior aspect of the left renal vein in the end-to-side fashion. At 22 months after the initial surgery, the patient underwent partial lung resection for a metachronous lung metastasis. For 6 years after the initial surgery, the venous reconstructions have maintained their patency without any obstruction of splenic venous flow, and the patient has remained in good health without further metastases or recurrences. This case has shown the importance of early diagnosis of carcinoma of the head of the pancreas, as appropriate and timely surgical management can result in good outcome. This patient responded well and remains alive six years following pancreaticoduodenectomy and preservation of the spleen with the use of a distal splenorenal shunt.

Multidisciplinary management of locally advanced pancreatic adenocarcinoma: Biology is King

The annual incidence of pancreatic cancer is nearly 50,000 patients. The 5-year overall survival is only 9%, and there remains a great need for better therapy. A subset of these patients presents with locally advanced disease. Multidisciplinary therapy has evolved to include some combination of systemic chemotherapy, locoregional radiation, and surgery in select patients with excellent biology. This review will address the thoughtful evidence-based and individualized approach to these patients.

Irreversible electroporation of locally advanced pancreatic cancer

Locally advanced pancreatic cancer (LAPC) constitutes approximately one-third of all pancreatic cancer, with standard of care inconsistently defined and achieving modest outcomes at best. While resection after downstaging offers the chance for cure, only a fraction of patients with LAPC become candidates for resection. Chemotherapy remains the mainstay of treatment for the remainder. In these patients, ablative therapy may be given for local control of the tumor. Irreversible electroporation (IRE) is an attractive ablative technique. IRE changes the permeability of tumor cell membranes to induce apoptosis. Unlike other ablative therapies, IRE causes little thermal injury to the target area, making it ideal for LAPC involving major vessels. Compared to systemic chemotherapy alone, IRE seems to offer some survival benefit. Although early studies reported notable morbidity and mortality rates, IRE presents opportunities for those who cannot undergo resection and who otherwise have limited options. Another role of IRE is to extend the margins of resected tumors when there is a concern for R1 resection. Perhaps most exciting, IRE is thought to have effects beyond local ablation. IRE has immunomodulatory effects, which may induce in vivo vaccination and may potentially synergize with immunotherapy. Through electrochemotherapy, IRE may enhance drug delivery to residual tumor cells. Ultimately the role of IRE in the treatment of LAPC still needs to be validated through well designed randomized trials. Investigations of its future possibilities are in the early stages. IRE offers the potential to provide more options to LAPC patients.

Survival Comparison of Neoadjuvant Chemotherapy Followed by Irreversible Electroporation Versus Conversional Resection for Locally Advanced Pancreatic Cancer

Locally advanced pancreatic cancer (LAPC) is a lethal disease and neoadjuvant chemotherapy and conversional resection is shown to provide the best survival for LAPC patients. Irreversible electroporation (IRE) is a new and effective method for the treatment of LAPC. This study aimed to compare the long-term survival of LAPC patients after neoadjuvant chemotherapy followed by conversional resection and IRE. A total of 140 LAPC patients were included from August 2015 to March 2020. The survival outcomes of patients after treatment with chemotherapy, chemotherapy combined with conversional resection or IRE were analyzed and compared. Patients in these three groups had similar clinical and pathological characteristics. Patients in the resection and IRE groups had similar median OS time (resection group vs. IRE group: 25.3 months vs. 26.0 months, P>0.050), which was significantly longer than that of the chemotherapy group (8.7 months, P<0.001). Additionally, patients in the resection and IRE groups had a median PFS of 10.6 and 12.0 months, respectively. Also, they were significantly higher than that of patients in the chemotherapy group. Chemotherapy combined with conversional resection and IRE was identified as significant prognostic factors for OS and PFS in LAPC patients. It was shown that compared with neoadjuvant chemotherapy followed by surgical resection, chemotherapy and IRE provided similar OS and PFS for LAPC patients with minimal invasion. This combination therapy may be a suitable treatment for LAPC patients.