Safety and Efficacy of EUS-Guided Ethanol Ablation for Treating Small Solid Pancreatic Neoplasm

Abstract

The strategy for treating small borderline malignant pancreatic neoplasms--such as neuroendocrine tumor (NET) and solid pseudopapillary neoplasm (SPN)--is surgical resection. However, pancreatic resection of these lesions still causes significant morbidity. We evaluated the safety and efficacy of EUS-guided ethanol ablation to treat small solid pancreatic neoplasms. A total of 8 patients with small borderline malignant pancreatic neoplasms and co-morbidities who refused surgery were included. We identified 2 cases of nonfunctioning NET, 3 cases of insulinomas, 1 case of gastrinoma, and 2 cases of SPN. EUS-guided ethanol ablation was performed, and treatment outcomes were assessed with clinical symptom, hormone assay, and imaging study. The mean tumor diameter was 15 mm (range, 7-29 mm), and the median volume of injected ethanol was 2.8 mL (range, 1.2-10.5 mL). There was 1 severe acute pancreatitis after EUS-guided ethanol ablation with 20-gauge CPN needle. During follow-up (median 16.5 months), 6 patients achieved treatment success; however, 2 patients (1 nonfunctioning NET and 1 SPN) still had persistent tumors. The patient with persistent SPN underwent surgical resection and the histopathological results showed peripancreatic infiltration with perineural invasion. Among 6 patients who achieved initial treatment success, 1 patient experienced tumor recurrence within 15 months and underwent repeated EUS-guided ethanol ablation. In conclusion, EUS-guided ethanol ablation therapy is a promising option for patients with small solid pancreatic neoplasm. Multiple sessions or surgical interventions may be required if there is a recurrent or persistent mass, and procedure-related adverse events must be carefully monitored.

FIGURE 1

(A) Computed tomography (CT) scan showing an 18-mm strong enhancing mass in the head of the pancreas (white arrow). (B) Acute pancreatitis developed 1 d after ethanol ablation therapy. Complicated loculated fluid and air are present in the head of the pancreas, adjacent to the enhancing mass. (C) CT scan taken 10 d after treatment showing aggravated peripancreatic infiltration. (D) CT scan taken 1 y after treatment showing that the peripancreatic infiltration had nearly disappeared. The enhancing mass still persisted in the head of the pancreas, although the volume of the mass had decreased (white arrow).

FIGURE 2

(A) Early homogenous enhancing insulinoma on contrast-enhanced harmonic EUS (CEH-EUS) before ethanol ablation therapy. (B) After treatment, no enhancement inside the tumor could be observed on CEH-EUS.

FIGURE 3

A 32-y-old male patient with hypoglycemia was diagnosed with insulinoma. A well-defined hypoechoic lesion in the head of pancreas is shown on EUS.

FIGURE 4

(A) Magnetic resonance imaging (MRI) showing a 20-mm well-demarcated solid mass in the head of the pancreas. The tumor was diagnosed as a solid pseudopapillary neoplasm on EUS-guided fine-needle biopsy. (B) The tumor had almost disappeared after ethanol ablation therapy.