Does previous biopsy lead to cancer overdiagnosis of superficial non-ampullary duodenal epithelial tumors?

Endoscopic diagnosis and treatment of superficial non-ampullary duodenal epithelial tumors: A review

The surface of the small bowel mucosa is covered more than any other section of the digestive canal; however, the overall prevalence of small bowel tumors of the whole gastrointestinal tract is evidently low. Owing to the improvement in endoscopic techniques, the prevalence of small bowel tumors has increased across multiple countries, which is mainly due to an increase in duodenal tumors. Superficial non-ampullary duodenal epithelial tumors (SNADETs) are defined as tumors originating from the non-ampullary region in the duodenum that share similarities and discrepancies with their gastric and colorectal counterparts in the pathogenesis and clinicopathologic characteristics. To date, white light endoscopy (WLE) remains the cornerstone of endoscopic diagnosis for SNADETs. Besides, narrow-band imaging (NBI) techniques and magnifying endoscopy (ME) have been widely used in the clinic and endorsed by multiple guidelines and consensuses for SNADETs' evaluation. Confocal laser endomicroscopy (CLE), endocytoscopy (ECS), and artificial intelligence (AI) are also up-and-coming methods, showing an exceptional value in the diagnosis of SNADETs. Similar to the endoscopic treatment for colorectal polyps, the choices for SNADETs mainly include cold snare polypectomy (CSP), endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and laparoscopic endoscopic cooperative surgery (LECS). However, owing to the narrow lumen, rich vascularity, weak muscle layer, abundant Brunner's gland, and the hardship of endoscope control, the duodenum ranks as one of the most dangerous operating areas in the digestive tract. Therefore, endoscopists must anticipate the difficulties in endoscopic maneuverability, remain aware of the increased risk of complications, and then select the appropriate treatment according to the advantages and disadvantages of each method.

Current status and perspectives for endoscopic diagnosis of superficial nonampullary duodenal epithelial tumors

In recent years, there have been significant advances in the endoscopic resection (ER) procedures of superficial nonampullary duodenal epithelial tumors (SNADETs). A preoperative endoscopic diagnosis is thus deemed necessary in determining the indication for subsequent ER. For the histologic and endoscopic diagnosis of SNADETs, understanding the mucin phenotype is inevitable. Recently, two diagnostic algorithms for the differential diagnosis of SNADETs from nonneoplastic lesions under magnifying endoscopy with narrow-band imaging have been proposed. In addition, various endoscopic approaches have been proposed to differentiate low- and high-grade adenomas/carcinomas, including white light endoscopy, magnifying image-enhanced endoscopy, and endocytoscopy. These methods, however, have not been standardized with respect to the classification of their findings and the validation of their diagnostic accuracy. Moreover, there are still concerns with respect to the histologic criteria required to establish a SNADETs diagnosis. Standardization in the histologic and endoscopic diagnosis of SNADETs is needed.