Efficacy and predictive factors of endoscopic ultrasound-guided ethanol ablation in benign solid pancreatic tumors

BACKGROUNDS AND OBJECTIVES: Endoscopic ultrasound-guided ethanol ablation (EUS-EA) has recently been introduced for the management of solid pancreatic tumors, including pancreatic neuroendocrine tumors (PNETs) and solid pseudopapillary tumors (SPTs). The study aims to evaluate the efficacy and predictive factors for response of EUS-EA in solid pancreatic tumors. METHODS: Between October 2015 and July 2021, 72 patients who underwent EUS-EA for solid pancreatic tumors were included. The study outcomes were to evaluate the efficacy of EUS-EA with complete remission (CR) and objective response, and their predictive factors. RESULTS: During follow-up, 47 patients were diagnosed with PNETs and 25 with SPTs. Eight cases reached CR and 48 reached objective response. When compared with SPTs, PNETs showed similar duration to reach CR (median not reached; p = 0.319), but shorter duration to reach objective response (PNETs: median 20.6 months, 95%CI 10.26–30.88; SPTs: median 47.7 months, 95%CI 18.14–77.20; p = 0.018). Ethanol dosage > 0.35 ml/cm(3) shortened the duration to reach CR (median not reached; p = 0.026) and objective response (median 42.5 months, 95%CI 25.34–59.66 vs. 19.6 months, 95%CI 10.17–29.09; p = 0.006). CR had no significant predictive factors, but PNETs showed significant predictive factors for objective response (HR 3.34, 95%CI 1.07–10.43; p = 0.038). Twenty-seven patients experienced adverse events, and there were two severe cases. CONCLUSION: EUS-EA for pancreatic solid lesions seems feasible as a local treatment for patients who refuse or are unfit for surgery. Additionally, PNETs seem to be the better candidate for EUS-EA.