Efficacy and safety of endoscopic ultrasonography-guided ethanol injections of small pancreatic neuroendocrine neoplasms: a prospective multicenter study

Background Endoscopic ultrasonography (EUS)-guided ethanol injection (EI) has recently been introduced as one of the management strategies for pancreatic neuroendocrine neoplasms (PNENs); however, its role as a surgical alternative is unclear. We evaluated the efficacy and safety of EUS-EI in treating small PNENs through a prospective multicenter study. Methods Patients with grade 1 tumors of ≤15mm confirmed by pathology were included. The primary end point assessed efficacy and safety, measuring complete ablation using computed tomography at 1 and 6 months, prevention of adverse events (AEs) within 1 month, severe pancreatic fistula at 1 month, and incidence/worsening of diabetes mellitus (DM) at 6 months. The composite end point of EUS-EI was compared with that of historical results of a study based on surgical treatment. Results 25 patients with PNENs, with a median tumor size of 10.1mm, were treated using EUS-EI. The composite primary end point was achieved by 76.0% of patients (19/25; 95%CI 54.9%-90.6%), a proportion significantly higher than that of surgical treatment (P = 0.008). Regarding efficacy, 88.0% (22/25) of patients achieved complete ablation at 1 and 6 months (95%CI 68.8%-97.5%). Regarding safety, 96.0% (24/25) of patients had no severe AEs within 1 month (95%CI 79.7%-99.9%). No patients had severe pancreatic fistulas at 1 month, and 84.0% (21/25) had no incidence or exacerbation, or both, of DMat 6 months (95%CI 63.9%- 95.5%). Conclusion EUS-EI is safe and could be a potent treatment option for patients with small PNENs.