Variation of tumoral marker after radiofrequency ablation of pancreatic adenocarcinoma

Endoscopic Ultrasound-Guided Laser Ablation Using a Diffusing Applicator for Locally Advanced Pancreatic Cancer Treatment

Simple Summary

Pancreatic cancer (PC) is one of the most lethal cancers; caused by family history, obesity, diabetes, and smoking, it has a 2–9% five-year survival rate. However, patients diagnosed by endoscopic ultrasound (EUS) already have an advanced stage of PC, indicating the difficulty of surgical resection. Recently, laser ablative treatment with a diffusing applicator has been proven to be feasible for treating advanced PC. Despite the potential application for treating PC, further evaluation of acute and chronic tissue responses are essential to determine the efficacy and safety of diffusing applicator under EUS guidance. In this study, EUS-guided diffusing applicator-assisted laser ablation was evaluated to quantify the extent of the tissue response after the delivery of various energy levels.

Abstract

Endoscopic ultrasound (EUS)-guided cylindrical interstitial laser ablation (CILA) procedures can be used to treat unresectable pancreatic cancer (PC). The aim of this study was to investigate the acute responses of pancreatic tissue after EUS-guided CILA in vivo in porcine models. Eight pigs were tested to compare the effects of different energy levels on pancreatic tissue ablation. A 1064 nm laser system was used to deliver 5 W through a diffusing applicator. The EUS-guided CILA was performed under four different energies: 200, 400, 600, and 800 J. Three days after the experiments, histological analysis was performed. The CILA consistently generated circular coagulated necrosis (CN) in the cross-sectioned pancreatic tissue. The ablation diameter was linearly dependent on the total energy delivery. The area of the CN initially increased with total energy delivery but became saturated at 600 J. The width of the degenerative parenchyma (DP) in the native tissue beyond the CN region increased with the total energy up to 600 J, and then decreased afterward. EUS-guided CILA can be a feasible approach for treating PC. Further animal studies will investigate the chronic responses of the pancreatic tissue to examine the efficacy and safety of the proposed method for clinical translation.

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.

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.

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.

Palliative therapy in pancreatic cancer-interventional treatment with radiofrequency ablation/irreversible electroporation

Pancreatic cancer (PC) is a solid tumor with still a dismal prognosis. Diagnosis is usually late, when the disease is metastatic or locally advanced (LAPC). Only 20% of PC are amenable to surgery at the time of diagnosis and the vast majority of them, despite radically resected will unavoidably recur. The treatment of LAPC is a challenge. Current guidelines suggest to adopt systemic therapies upfront, based on multi-drugs chemotherapy regimens. However, the vast majority of patients will never experience conversion to surgical exploration and radical resection. Thus, there a large subgroup of LAPC patients where the only therapeutic chance is to offer palliative treatments, such as interventional ablative treatments, in order to obtain a cytoreduction of the tumor, trying to delay its growth and spread. Radiofrequency ablation (RFA) and irreversible electroporation (IRE) demonstrated to be safe and effective in obtaining a local control of the disease with some promising oncological results in terms of overall survival (OS). However, they should be adopted as a treatment strategy to adopt in parallel with other systemic therapies, within multidisciplinary choices. They are not free from complications, even serious, thus they should applied only in specialized centers of pancreatology. This review depicts the state of the art of the two techniques.

Computed tomography findings after radiofrequency ablation in locally advanced pancreatic cancer

Purpose

The purpose of the study was to provide a systematic evaluation of the computed tomography(CT) findings after radiofrequency ablation (RFA) in locally advanced pancreatic cancer(LAPC).

Methods

Eighteen patients with intra-operative RFA-treated LAPC were included in a prospective case series. All CT-scans performed prior to RFA and 1 week and 3 months of post-RFA, according to standard regimen, were assessed by two radiologists in consensus, using standardized radiological scoring lists.

Results

51 CT-scans were assessed. One week after RFA, the ablation zone was visible in all patients as a (partially) sharply defined (83%), heterogeneous area (94%). At 3 months of follow-up, the ablation zone was completely invaded by tumor in 67% of patients and still present, but decreased in 33%. In two patients (11%), local thrombosis and/or occlusion of the superior mesenteric vein occurred. The occlusions persisted without clinical consequences and the thrombosis disappeared. A peripancreatic fluid collection was visible 1 week after RFA in 3 patients, wherein the ablation zone extended ventrally outside of the pancreas.

Conclusions

Directly after RFA for LAPC, a well-defined ablation zone is visible on CT-imaging. This ablation zone is usually replaced by tumor ingrowth after 3 months. Moreover, the ablation zone regularly included vascular structures, with rare asymptomatic venous occlusion or thrombosis and without adverse effects on arteries.

Electronic supplementary material

The online version of this article (10.1007/s00261-018-1519-y) contains supplementary material, which is available to authorized users.

Radiofrequency ablation for locally advanced pancreatic cancer: SMAD4 analysis segregates a responsive subgroup of patients

PURPOSE

SMAD4 mutational status correlates with pancreatic ductal adenocarcinoma (PDAC) failure pattern. We investigated in a subset of locally advanced patients submitted to radiofrequency ablation (RFA) whether the assessment of SMAD4 status is a useful way to select the patients.

METHODS

Clinical, radiological, and follow-up details of patients submitted to RFA for locally advanced pancreatic cancer (LAPC), in whom cytohistological material was available at our institution, were retrospectively retrieved. SMAD4 expression was evaluated by immunohistochemistry (IHC) and considered "negative" or "positive." The survival analysis was conducted using Kaplan-Meier and Cox proportional hazards models.

RESULTS

The study population consisted of 30 patients. Thirteen patients (43.3%) received RFA upfront, whereas 17 (56.7%) after induction treatments. SMAD4 was mutant in 18 out of 30 patients (60%). The overall estimated post-RFA disease-specific survival (DSS) was 15 months (95% CI 11.64-18.35). The estimated post-RFA DSS of patients with wild-type and mutant SMAD4 was 22 and 12 months, respectively (log-rank p < 0.05). At the multivariate analysis, SMAD4 was the only independent predictor of survival (p = 0.05). The pattern of failure was not associated with SMAD4 status (p = 0.4).

CONCLUSIONS

Within patients undergoing RFA for LAPC, SMAD4 analysis could segregate a subgroup of subjects with improved survival, who likely benefited from tumor ablation.

Percutaneous Radiofrequency Ablation of Unresectable Locally Advanced Pancreatic Cancer: Preliminary Results

AIM

The objective of this study was to evaluate the efficacy of percutaneous radiofrequency ablation of locally advanced pancreatic cancer located in the pancreatic body.

MATERIALS AND METHODS

Patients with biopsy-proven locally advanced pancreatic adenocarcinoma were considered for percutaneous radiofrequency ablation. Postprocedural computed tomography studies and Ca19.9 tumor marker evaluation were performed at 24 hours and 1 month. At computed tomography, treatment effect was evaluated by excluding the presence of complications. The technical success of the procedure is defined at computed tomography as the achievement of tumoral ablated area.

RESULTS

Twenty-three patients have been included in the study. Five of the 23 patients were excluded. At computed tomography, the mean size of the intralesional postablation necrotic area was 32 mm (range: 15-65 mm). Technical success of the procedure has been obtained in 16 (93%) of the 18 cases. None of the patients developed postprocedural complications. Mean Ca19.9 serum levels 1 day before, 1 day after, and 1 month after the procedure were 285.8 U/mL (range: 16.6-942.0 U/mL), 635.2 U/mL (range: 17.9-3368.0 U/mL), and 336.0 U/mL (range: 7.0-1400.0 U/mL), respectively. Follow-up duration was less than 6 months for 11 patients and more than 6 months for 7 patients. At the time of the draft of this article, the mean survival of the patients included in the study was 185 days (range: 62-398 days).

CONCLUSION

Percutaneous radiofrequency ablation of locally advanced adenocarcinoma has a high technical success rate and is effective in cytoreduction both at imaging and laboratory controls.