Endoscopic diagnosis and treatment of superficial nonampullary duodenal tumors

The diagnostic and treatment guidelines of superficial non-ampullary duodenal tumors have not been standardized due to their low prevalence.Previous reports suggested that a superficial adenocarcinoma(SAC) should be treated via local resection because of its low risk of lymph node metastasis,whereas a highgrade adenoma(HGA) should be resected because of its high risk of progression to adenocarcinoma.Therefore,pretreatment diagnosis of SAC or HGA is important to determine the appropriate treatment strategy.There are certain endoscopic features known to be associated with SAC or HGA,and current practice prioritizes the endoscopic and biopsy diagnosis of these conditions.Surgical treatment of these duodenal lesions is often related to high risk of morbidity,and therefore endoscopic resection has become increasingly common in recent years.Endoscopic mucosal resection(EMR) and endoscopic submucosal dissection(ESD) are the commonly performed endoscopic resection methods.EMR is preferred due to its lower risk of adverse events;however,it has a higher risk of recurrence than ESD.Recently,a new and safer endoscopic procedure that reduces adverse events from EMR or ESD has been reported.