Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) and endoscopic ultrasound-guided ethanol ablation (EUS-EA) of pancreatic neuroendocrine tumors and adenocarcinoma: a prospective multicenter study

Introduction
Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) and endoscopic ultrasound-guided ethanol ablation (EUS-EA) are emerging novel methods for managing non-functioning and functioning pNET and adenocarcinoma in the pancreas.

Aim
To assess the safety profile, feasibility, and outcomes of EUS-RFA and EUS-EA of focal pancreatic masses.

Material and methods
This prospective study included 27 patients, 15 males and 12 females, with a mean age of 36.38 years. EUS-RFA was carried out in 13 patients; 11 had pancreatic insulinoma, and 2 had advanced pancreatic adenocarcinoma. The mean size of the masses was 20.6 mm, while that of the insulinomas was 17.4 mm. The median number of needle passes was 3, with a range of 1 to 6. RFA was conducted using 19G EUSRA needles from Taewoong Co., Ltd., South Korea. No minor or major complications were observed. EUS-EA was carried out in 14 patients, all of whom had pancreatic insulinoma. The mean size of the masses was 15.3 mm. The median number of needle passes was 2, with a range of 1 to 3. We used 19G and 22G echo tip FNA needles from Cook Company, USA. The mean duration of follow-up was 12.4 months. There was mild to moderate acute pancreatitis in 4 patients in the EUS-EA group; all were relieved by conservative therapy, and no hospital admission was required. No early or late significant complications were reported in the EUS-RFA group.

Results
There was a complete clinical cure of 10 out of 11 (91%) patients with pancreatic insulinoma who underwent EUS-RFA. However, 1 patient required three sessions, and 2 patients required two sessions of EUS-RFA. The 11th patient with insulinoma showed a poor response after the first session, then a partial response after the second session of EUS-RFA. The size of the two masses with advanced adenocarcinoma was decreased, but no downstaging of the masses was achieved. There was a complete clinical cure of 8 out of 14 (57%) patients with pancreatic insulinoma who underwent EUS-EA. No clinical cure was observed in 4 patients; 3 underwent major surgery, and the 4th one underwent EUS-RFA. The last 2 patients showed a partial clinical response with decreased frequency, duration, and severity of hypoglycemic attacks. They were managed by diet regulation; no major surgery was needed.

Conclusions
EUS-RFA and EUS-EA can potentially treat lesions and control symptoms. EUS-RFA is a more promising and safer technique for managing functioning insulinomas. However, it cannot downstage pancreatic ductal adenocarcinoma patients. EUS-EA seems less efficient, with more adverse events than EUS-RFA.