LAUSR

Dear Editor, I read with great interest the article by Dasari et al. It comprehensively covered the current literature regarding surgical and endoscopic management of duodenal NETs. The authors note positive resection margins in 22 of 51 cases; this gives an R0 resection rate of 56%. The eight studies in this literature review covered a period from 2010 to 2016; in total, 95 patients underwent a form of endoscopic resection ranging from biopsy excision, snare resection and endoscopic mucosal resection. These techniques are all associated with low R0 resection margins. It is important to mention to readers the rapidly developing endoscopic techniques, specifically endoscopic mucosal dissection (ESD) and hybrid resection techniques, which enable higher rates of en bloc and R0 resections. In recent years, ESD, which is a well-established technique for resection of colonic and gastric tumours, has begun to be undertaken in the duodenum. Kim et al. reported a singlecentre experience of 62 cases (64 lesions) of duodenal subepithelial lesions which were resected endoscopically using endoscopic mucosal resection with band ligation, ESD or standard EMR. In this series, a complete resection rate of 100% and a histopathological R0 resection rate of 76.6%were achieved. Fujimoto et al. recently reported on a series of ten patients with duodenal NET resected using EMR with a ligation device, again in this series, achieving R0 resection of 70%. There are other case series reporting similar findings with much higher R0 resection rates. As the authors suggest, careful assessment of the lesion with endoscopic ultrasound can help determine the depth of tumour invasion. For lesions less than 2 cm, endoscopic resection can be performed using advanced endoscopic resection methods safely and with a high probability of achieving an R0 resection.