Role of Endoscopic Ultrasound Ablative Therapy in Management of Pancreatic Neuroendocrine Tumors: a Systematic Review

Pancreatic neuroendocrine tumors (PNET) represent less than 3% of all primary pancreatic tumors. With the advent of advanced imaging techniques (computed tomography/magnetic resonance imaging/endoscopic ultrasonography), the proportion of incidentally detected small PNET (less than 2 cm) has increased. As surgery in small and/or nonfunctional PNET carries significant morbidity and mortality and is considered as overtreatment, newer methods, viz., EUS-guided radiofrequency ablation and ethanol/ethanol-lipoidal ablation, have been reported with variable success. We reviewed the current literature regarding EUS-guided ablative therapy (EUSGAT) for PNETs. We performed a systematic review, regarding the indications, efficacy, complications, mortality, and morbidity of EUSGAT in management of PNET. Seven prospective studies including 95 PNET patients were identified after systematic search. There were no randomized controlled trials. Among 95 patients, 81% (n = 77) had nonfunctional tumors and 19% (n = 18) had functional tumors. Indication for selecting EUSGAT over surgery was poor functional status of patients. The overall effectiveness of EUSGAT was 90.5% (54-98%) without differences between functional vs. nonfunctional PNETs (p = 0.3). Major complication in the form of pancreatitis was observed in 10.5% (n = 10) patients, and there was no mortality. EUSGAT has acceptable effectiveness rate only for small PNETs. However, associated complication rate is also a cause for concern. As per current evidence, we can only suggest that EUS-guided strategy should be used as experimental therapy in clinical study settings only after discussing goals of treatment and potential complications.