Endoscopic ultrasound-guided radiofrequency ablation of the pancreas: An experimental study with pathological correlation

Abstract

Background: The treatment of pancreatic cancer represents a major objective in clinical research, as it still remains the fourth leading cause of cancer deaths among men and women, with approximately 6% of all cancer-related deaths.

Materials and methods: We studied the assessment of an endoscopic ultrasound (EUS)-guided radiofrequency ablation (RFA) probe through a 19G needle in order to achieve a desirable necrosis area in the pancreas. Radiofrequency ablation of the head of the pancreas was performed on 10 Yorkshire pigs with a weight between 25 kg and 35 kg and a length of 40-70 cm. Using an EUS-guided RFA experimental probe, we ablated an area of 2-3 cm width. The biological samples were harvested after 3 days and 5 days and necropsy was performed 1 week after the procedure.

Results: All pigs showed no significant change regarding their behavior and no signs of complication was encountered. Blood analysis revealed increased values of amylase, alkaline phosphatase, and gamma-glutamyl transpeptidase on the 3rd day but a decrease on the 5th day. After necropsy and isolation of the pancreas, the ablated area was easily found, describing a solid necrosis. The pathological examination revealed a coagulative necrosis area with minimal invasion and inflammatory tissue at about 2 cm surrounding the lesion.

Conclusion: EUS-RFA is a feasible technique and might represent a promising therapy for the future treatment of pancreatic cancer. However, further studies are necessary to investigate EUS-guided RFA as an option for palliation in pancreatic cancer until it can be successfully used in human patients.

Figure 1

Habib™ RF DUO 13 (0.33 mm, 0.013”), with a working length of 200 cm was inserted through a 19G endoscopic ultrasound-fine-needle aspiration (EUS-FNA) needle (Olympus, Tokyo, Japan)

Figure 2

EUS image with the radiofrequency ablation (RFA) probe prior ablation

Figure 3

EUS image with the RFA probe after ablation

Figure 4

Exposure of the pancreas during necropsy

Figure 5

Ablation area in the pancreas

Figure 6

Pathological scan of the entire ablation area: central necrosis area (a) surrounded by lizereum inflammatory demarcation (b, fibrinous exudate + neutrophils) followed by a granulation tissue (c), which changes to the periphery into a collagen dense tissue (d) separating it from adjacent normal parenchyma. Col Tricromic Masson, X4 (for all detailed images A-D, the magnification was ×100)