Up to 13.5% of patients that undergo a magnetic resonance imaging (MRI) scan of their abdomen without pancreatic symptoms are found to have an incidental pancreatic cyst, with the frequency increasing with age. In a post-mortem series, 25% of patients had a pancreatic cyst, of which 32% were potentially premalignant and 3% malignant. Premalignant cysts are currently either observed or removed surgically according to international guidelines. Observation is associated with significant anxiety for patients and a growing cost to the National Health Service, while surgery for this usually benign condition is associated with not insignificant morbidity and mortality. Premalignant pancreatic cysts may be indolent for a number of years before malignant transformation, creating a window of opportunity for minimally invasive intervention and cure. New early treatment options for premalignant tumours are urgently required. This study will evaluate the safety and efficacy of a novel minimally invasive technique for the treatment of pancreatic cystic tumours; endoscopic ultrasound guided radiofrequency ablation (EUSRFA).