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.

ESGE suggests conventional endoscopic submucosal dissection (ESD; marking and mucosal incision followed by circumferential incision and stepwise submucosal dissection) for most esophageal and gastric lesions. ESGE suggests tunneling ESD for esophageal lesions involving more than two-thirds of the esophageal circumference. ESGE recommends the pocket-creation method for colorectal ESD, at least if traction devices are not used. The use of dedicated ESD knives with size adequate to the location/thickness of the gastrointestinal wall is recommended. It is suggested that isotonic saline or viscous solutions can be used for submucosal injection. ESGE recommends traction methods in esophageal and colorectal ESD and in selected gastric lesions. After gastric ESD, coagulation of visible vessels is recommended, and post-procedural high dose proton pump inhibitor (PPI) (or vonoprazan). ESGE recommends against routine closure of the ESD defect, except in duodenal ESD. ESGE recommends corticosteroids after resection of  > 50 % of the esophageal circumference. The use of carbon dioxide when performing ESD is recommended. ESGE recommends against the performance of second-look endoscopy after ESD. ESGE recommends endoscopy/colonoscopy in the case of significant bleeding (hemodynamic instability, drop in hemoglobin > 2 g/dL, severe ongoing bleeding) to perform endoscopic hemostasis with thermal methods or clipping; hemostatic powders represent rescue therapies. ESGE recommends closure of immediate perforations with clips (through-the-scope or cap-mounted, depending on the size and shape of the perforation), as soon as possible but ideally after securing a good plane for further dissection.

The standard treatment of locally advanced rectal cancer is chemoradiation (CRT) followed by proctectomy and adjuvant chemotherapy. However, there is an emerging role for nonsurgical management after CRT or total neoadjuvant therapy (TNT) consisting of CRT and neoadjuvant chemotherapy. Endoscopic submucosal dissection (ESD) after CRT or TNT for rectal cancer, termed "salvage ESD," may be a viable nonsurgical option for carefully selected patients. We aimed to evaluate the feasibility and safety of salvage ESD.

A retrospective chart review of cases of salvage ESD for locally advanced rectal cancer and standard ESD for rectal tumors without prior CRT from July 2018 to August 2020 at our institution was performed. Clinical factors and imaging, procedural, and pathology results were collected and compared.

Twelve salvage ESD cases were compared with 27 standard ESD cases. Before CRT, 83.3% of lesions in the salvage ESD group were initially clinically staged as T3. The en-bloc resection rates were 92.7% and 91.7% (P = 1.00) and R0 resection rates 66.7% and 75.0% (P = .55) for the standard and salvage groups, respectively. In the salvage ESD group, no adverse events were observed, and 75.0% of the adenocarcinomas in the salvage ESD group had morphologically changed to hyperplasia or adenoma after CRT, with no identifiable lesions greater than T1 tumor depth.

Salvage ESD for locally advanced rectal cancer is technically feasible with low adverse event rates. There may be a diagnostic role in salvage ESD in assessing pathologic response to CRT and a possible therapeutic role in resection of residual lesions with the potential to avoid surgery.

Though superficial non-ampullary duodenal epithelial tumors (SNADETs) have been traditionally considered rare, there is a growing detection under the development and widespread of endoscopic techniques in recent times. Many case studies have revealed early manifestations of lesions through advanced endoscopic technology, however, because of the low incidence of duodenal tumors and challenges in diagnosing, the preoperative diagnosis criteria have not been established so far. In spite of this, recently the increasing detection rate of early duodenal epithelial lesions enhances the demand for minimally invasive treatment as well. The most suitable therapeutic endoscopic modality to remove duodenal lesions should be selected according to the size, location and histological invasive depth of duodenal lesions. Nevertheless, due to the special anatomical structure of the duodenum, the incidence of complications is much higher than in any other part of the digestive tract. To prevent these adverse events prophylactically, a few novel strategies have been applied effectively after resection. This review describes the current status of preoperative endoscopic diagnosis and endoscopic resection approaches, as well as countermeasures for avoiding procedure-related complications.

The natural history of sporadic non-ampullary duodenal epithelial tumors (SNADETs) is poorly documented. The aim of this study was to evaluate the history of SNADETs in patients where immediate resection could not be performed.

This is a single-center retrospective study of 86 consecutive cases of SNADETs who did not undergo immediate resection and were followed-up with upper gastrointestinal endoscopy for more than 6 months.

During a follow-up period of 36.8 (6.0-613.0) months, macroscopic progression was admitted in eight (9.3%). Of these, the final histology in four was adenocarcinoma, and three cases demonstrated submucosal invasion. Rates of macroscopic progression at 150 months after detection were 11.1%, 16.7%, and 30.0% for SNADETs <5 mm, <10 mm, and ≥10 mm, respectively.

The overall risk of SNADETs progressing to invasive cancer is low. However, changes in macroscopic size or shape of SNADETs signify a high risk of progression to invasive cancer.

Background: Traction-assisted endoscopic resection is an approach to provide better procedural outcomes than conventional endoscopic procedure in treating gastric or esophageal epithelial lesions. Submucosal tumors (SMTs) are challenging to resect endoscopically due to the difficulty in exposure and high incidence of full-thickness resection. In this study, we investigated the efficacy of snare traction-assisted method, served as an "extra hand," for upper gastrointestinal SMTs. Methods: From June 2019 to May 2020, we used the snare traction-assisted method to treat 11 patients with 12 upper gastrointestinal SMTs in the Sixth Affiliated Hospital, Sun Yat-sen University. The duration of the procedures and the outcomes were recorded. Results: A total of 11 patients with 12 lesions were treated by snare traction-assisted endoscopic resection. The mean procedure time was 26.8 ± 8.3 minutes. En bloc resection was achieved in all the 12 lesions. The mean length of the specimens was 11.5 ± 4.0 mm. Full-thickness resection was performed in four lesions. The patients were discharged in 5.0 days after procedures without delayed bleeding or other complication reported. Conclusion: Snare traction-assisted method is an effective tool for endoscopic resection of upper gastrointestinal SMTs. Further prospective studies comparing the snare traction-assisted method with the conventional procedure are necessary.

Background and study aims  Duodenal endoscopic submucosal dissection (ESD) is still considered technically challenging; however, few studies have objectively analyzed predictors of the technical difficulty. Therefore, the aim of the current study was to elucidate predictors of the technical difficulty of duodenal ESD. Patients and methods  This was a retrospective observational study. From June 2010 to June 2017, a total of 174 consecutive patients with superficial duodenal epithelial neoplasia who underwent ESD were included in this study. We tried to identify predictors for technical difficulty of ESD by defining technical difficulty as either procedure time > 100 minutes or intraprocedural perforation. Moreover, we constructed a scoring system consisting of factors that were significant in the multivariate analysis. Results  The proportion of patients with technical difficulty was 34.5 %. In the multivariate analysis, lesion location in flexural part [odds ratio (OR), 2.61; 95 % confidence interval (CI), 1.02 - 6.68], larger lesion size (> 40 mm) (OR, 5.26; 95% CI, 2.15 - 12.9), and occupied circumference > 50 % of the duodenum (OR, 5.80; 95 % CI, 1.83 - 18.4) were associated with technical difficulty. Conclusion  A lesion location in flexural part, lesion size >40 mm and occupied circumference > 50 % were risk factors for technical difficulty of duodenal ESD.