Treatment strategies for small pancreatic neuroendocrine tumors (PNETs) <2 cm in size are still under debate. The feasibility and safety of EUS-guided ethanol ablation (EUS-EA) have been demonstrated. However, sample sizes in previous studies were small with no comparative studies on surgery. Therefore, we aimed to compare the safety and long-term outcomes of EUS-EA with those of surgery for the management of nonfunctioning small PNETs.

We retrospectively reviewed patients with PNETs who were managed by EUS-EA (from 2011 to 2018) and surgery (from 2000 to 2018) at Asan Medical Center. Propensity score matching (PSM) was performed to increase comparability. The primary outcome was early and late major adverse events (Clavien-Dindo grade ≥III) after treatment. Secondary outcomes were 10-year overall (OS) and disease-specific survival (DSS) rates, length of hospital stay, and development of endocrine pancreatic insufficiency.

Of all patients, 97 and 188 patients were included in the EUS-EA and surgery groups, respectively. PSM created 89 matched pairs. EUS-EA was associated with a significantly lower rate of early major adverse events (0% vs 11.2%, P = .003). Late major adverse events occurred more frequently after surgery, with no significant difference between groups (3.4% vs 10.1%, P = .07). Both treatment modalities showed comparable 10-year OS and DSS rates. The length of hospital stay was significantly shorter in the EUS-EA group (4 days vs 14.1 days, P < .001), and endocrine pancreatic insufficiency was less common after EUS-EA than after surgery (33.3% vs 48.6%, P = .121).

EUS-EA had fewer adverse events and a shorter hospital stay with similar OS and DSS rates compared with surgery, suggesting that EUS-EA may be a preferred alternative to surgical resection in selected patients with nonfunctioning small PNETs.