A Systematic Review about Imaging and Histopathological Findings for Detecting and Evaluating Electroporation Based Treatments Response

Abstract

Background: Imaging methods and the most appropriate criteria to be used for detecting and evaluating response to oncological treatments depend on the pathology and anatomical site to be treated and on the treatment to be performed. This document provides a general overview of the main imaging and histopathological findings of electroporation-based treatments (Electrochemotherapy—ECT and Irreversible electroporation—IRE) compared to thermal approach, such as radiofrequency ablation (RFA), in deep-seated cancers with a particular attention to pancreatic and liver cancer. Methods: Numerous electronic datasets were examined: PubMed, Scopus, Web of Science and Google Scholar. The research covered the years from January 1990 to April 2021. All titles and abstracts were analyzed. The inclusion criteria were the following: studies that report imaging or histopathological findings after ablative thermal and not thermal loco-regional treatments (ECT, IRE, RFA) in deep-seated cancers including pancreatic and liver cancer and articles published in the English language. Exclusion criteria were unavailability of full text and congress abstracts or posters and different topic respect to inclusion criteria. Results: 558 potentially relevant references through electronic searches were identified. A total of 38 articles met the inclusion criteria: 20 studies report imaging findings after RFA or ECT or IRE in pancreatic and liver cancer; 17 studies report histopathological findings after RFA or ECT or IRE; 1 study reports both imaging and histopathological findings after RFA or ECT or IRE. Conclusions: Imaging features are related to the type of therapy administrated, to the timing of re-assessment post therapy and to the imaging technique being used to observe the effects. Histological findings after both ECT and IRE show that the treated area becomes necrotic and encapsulated in fibrous tissue, suggesting that the size of the treated lesion cannot be measured as an endpoint to detect response. Moreover, histology frequently reported signs of apoptosis and reduced vital tissue, implying that imaging criteria, which take into account the viability and not the size of the lesion, are more appropriate to evaluate response to treatment.

Comments on “The beneficial role of electrochemotherapy in locally advanced pancreatic cancer - radiological perspective”

“…Therefore, in contrast to what was reported Dr Kozak and colleagues [1], IRE cannot be defined with the term of ECT, and, although both IRE and ECT can be safely used to treat LAPC patients, these techniques are profoundly different [6][7][8][9][10]. Some authors have evaluated the feasibility and effectiveness of electrochemotherapy on deep tumours [6][7][8][9][10][11][12][13][14][15][16][17][18]. In our previous study we showed that electrochemotherapy on pancreatic tumours can be performed safely and feasibly [6].…”

“…In conclusion, we believe that the readers of "Polish Journal of Radiology" should know that the term IRE should not be confused with the term electrochemotherapy, which is reserved for a combination of low doses of chemotherapeutic drugs with an electrical field that determines a transient increase of cell permeability (reversible electroporation) [13][14][15][16][17][18].…”

Complications Risk Assessment and Imaging Findings of Thermal Ablation Treatment in Liver Cancers: What the Radiologist Should Expect

“…In contrast to RFA and MWA, IRE and ECT [ 21 , 23 , 39 , 40 ] are non-thermal techniques that cause ablation by changing cell membrane permeability using an induced electric field (electroporation). IRE is considered a direct ablation tool, since electroporation is used in an irreversible manner, causing the irreversible permeabilization of the lipid bilayer, the disruption of cellular homeostasis and stimulation of apoptotic pathways, causing death of neoplastic cells.…”

“…One of the major fields of application of ablation treatment is liver tumors [ 21 , 22 , 23 , 24 ], with hepatocellular carcinoma (HCC) and metastases representing the principal targets [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. With respect to HCC, ablation treatments are considered as upfront treatments in patients with early-stage disease [ 24 ].…”

Risk Assessment and Pancreatic Cancer: Diagnostic Management and Artificial Intelligence

“…The high mortality rate is correlated with several factors, of which the main is the late disease stage at which the majority of patients are diagnosed [14][15][16][17][18][19][20][21][22][23][24][25][26]. In fact, pancreatic cancer is asymptomatic until the disease develops to an advanced stage, and at diagnosis only about 20% of cases are eligible for surgical resection [27][28][29][30][31][32]. In addition, even after the surgical approach, the majority of patients will experience a recurrence, with five-year survival only up to 25% [3,[33][34][35][36].…”