Endoscopic ultrasonography-guided ethanol ablation for small pancreatic neuroendocrine tumors: results of a pilot study

Abstract

Background/aims: Endoscopic ultrasonography (EUS)-guided ethanol ablation is gaining popularity for the treatment of focal pancreatic lesions. The aim of this study was to evaluate the safety, feasibility, and treatment response after EUS-guided ethanol injection for small pancreatic neuroendocrine tumors (p-NETs).

Methods: This was a retrospective analysis of a prospectively collected database including 11 consecutive patients with p-NETs who underwent EUS-guided ethanol injection.

Results: EUS-guided ethanol injection was successfully performed in 11 patients with 14 tumors. The final diagnosis was based on histology and clinical signs as follows: 10 non-functioning neuroendocrine tumors and four insulinomas. During follow-up (median, 370 days; range, 152 to 730 days), 10 patients underwent clinical follow-up after treatment, and one patient was excluded because of loss to follow-up. A single treatment session with an injection of 0.5 to 3.8 mL of ethanol resulted in complete responses (CRs) at the 3-month radiologic imaging for seven of 13 tumors (response rate, 53.8%). Multiple treatment sessions performed in three tumors with residual viable enhancing tissue increased the number of tumors with CRs to eight of 13 (response rate, 61.5%). Mild pancreatitis occurred in three of 11 patients.

Conclusions: EUS-guided ethanol injection appears to be a safe, feasible, and potentially effective method for treating small p-NETs in patients who are poor surgical candidates.

Keywords: Ablation; Endosonography; Ethanol; Neuroendocrine tumors.

Fig. 1. (A) Contrast-enhanced computed tomography (CT) scan showing a hypervascular mass in the pancreatic head. (B) Sonographic volumetric analysis of the tumor using 3-dimensional software. (C) Endoscopic ultrasonography-guided puncture of a neuroendocrine tumor. (D) Use of a 22-gauge needle for multiple injections of 99% ethanol until the hyperechoic blush extended to the margin of the tumor. (E) Eight-month follow-up CT scan showing successful ethanol ablation of a tumor.

Fig. 2. Study flowchart. CT, computed tomography; CE-EUS, contrast-enhanced endoscopic ultrasonography; NET, neuroendocrine tumor; EUS-FNA, endoscopic ultrasonography-guided fine-needle aspiration; 3D, 3-dimensional; CECT, contrast-enhanced computed tomography.