Endoscopic ultrasound-guided radiofrequency ablation for large branch-duct intraductal papillary mucinous neoplasms: Safety and efficacy trial

Abstract

Background and study aims: Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a nonsurgical treatment option for managing pancreatic lesions. We sought to evaluate the safety and efficacy of EUS-RFA for large (≥4 cm) branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs).

Patients and methods: Patients with a definitive diagnosis of BD-IPMN who declined or were unfit for surgery underwent EUS-RFA in a single-arm prospective trial. Ablation was performed using a 19G EUS-RFA needle. RFA applications were delivered up to a maximum threshold of 45 seconds or 400 ohms impedance. Safety was assessed using AGREE guidelines. Potential for efficacy was assessed using cyst volume and cyst fluid KRAS GNAS mutations using next-generation sequencing (NGS). Adverse events (AEs) were analyzed per RFA session, while response was analyzed per BD-IPMN.

Results: Thirty BD-IPMNs (mean diameter 4.6 ± 1.7 cm; 80% multilocular) in 25 participants (mean age 74.1 ± 8.3 years) underwent 41 EUS-RFA sessions. AEs occurred in 12.2% of procedures (5/41), the majority being AGREE Grade 3A (9.8%, 4/41). During a mean follow-up of 18 ± 5 months, 22 of 28 BD-IPMNs (78.6%) achieved ≥ 50% reduction in cyst volume, and 11 (39.3%) demonstrated complete (≥90%) response. Among 26 BD-IPMNs that revealed KRAS GNAS mutations, follow-up NGS was performed in 17, with 88.2% showing loss of detectable mutations.

Conclusions: EUS-RFA in large, predominantly multilocular BD-IPMNs shows promising volumetric efficacy. Safety may be improved through refined energy delivery and technical advances. Molecular response remains exploratory and requires further validation. Long-term studies assessing progression-free outcomes are needed to define its role as an organ-preserving therapeutic option.

Keywords: Endoscopic ultrasonography; Endoscopy Upper GI Tract; Intervention EUS; Pancreas; RFA and ablative methods.

Fig. 1

Study flow diagram. BD-IPMN, branch duct intraductal papillary mucinous neoplasm; EUS-RFA, endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA). ¹ BD-IPMN was not safely accessible due to intervening splenic vessels in the pancreatic tail. ² Eighty-four were excluded for the following reasons: absence of high-risk or worrisome features (n = 62), Clinical Frailty Score (CFS) >6 (n = 14), surgical candidacy (n = 7), and a recent episode of acute pancreatitis (n = 1).

Fig. 2

EUS-guided needle trajectory optimization for cystic lesions: longitudinal and perpendicular approaches. Schematic illustrating two approaches for EUS-RFA needle access in BD-IPMNs: (left) along the long axis using the elevator and big wheel of the EUS scope, and (right) along a perpendicular axis via scope rotation. For each point on the long axis, a corresponding perpendicular axis can be targeted, which is more feasible in body lesions than in those located in the pancreatic head or uncinate process.

Fig. 3

Representative volume reduction of BD-IPMNs assessed with MRI following endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA). Each row represents a single BD-IPMN from a unique participant, with the lesion highlighted in axial images (orange circle) and coronal images (pink circle). BD-IPMN volumes were quantified using region-of-interest (ROI) segmentation and computerized three-dimensional (3D) reconstruction. The respective post-RFA volume reductions for BD-IPMNs in Panels A, B, C, and D, are 97%, 54%, 94%, and 99%, respectively.