Hurdles of duodenal endoscopic submucosal dissection, delayed bleeding and perforation.

Abstract

Duodenal tumors are rare, but with the permeation of esophagogastroduodenoscopy, their detection has recently been increasing.1 Local resection, including endoscopic resection, has been proposed for superficial neoplasms such as high-grade adenoma or mucosal carcinoma that have negligible risk of metastasis.2 Similar to superficial neoplasms in other parts of the gastrointestinal (GI) tract, application of endoscopic submucosal dissection (ESD) rather than piecemeal or multiple sessions of endoscopic mucosal resection (EMR) has been introduced to duodenal lesions2 in order to achieve en bloc curative resection and to decrease the risk of local recurrence. However, duodenal ESD remains an aggressive treatment and carries a particularly high rate of complications compared to that of the esophagus, stomach and colorectum. In this issue of Digestive Endoscopy, Hoteya et al. report that endoscopic closure of the ulcer after duodenal ESD might reduce the risk of delayed bleeding.3 The authors analyzed a retrospective cohort of 63 patients who underwent duodenal ESD for superficial non-ampullary duodenal neoplasms in which the incidence of delayed bleeding was 17.5% (11/63). The incidence of perforation including four patients who underwent successive surgery was 31.3% (21/67). The high incidence of perforation of duodenal ESD has been reported in previous studies1, 4 and several contributory factors have been considered such as the thin duodenal wall, the narrow, curved lumen, and the duodenum being far from the mouth, all of which require that the endoscope be deeply inserted resulting in decreased maneuverability. The technical difficulty and high incidence of intraoperative perforation of duodenal ESD reflect these particular anatomical characteristics. However, what could be the risk of the high incidence of delayed bleeding? Delayed bleeding is a major complication of gastric ESD but is uncommon among esophageal or colorectal ESD. To decrease the risk of delayed bleeding after gastric ESD, preventive measures such as routine coagulation of visible vessels of the ulcer immediately after ESD5 or administration of proton pump inhibitors have been established.6 In terms of duodenal ESD, the incidence of delayed bleeding in a multicenter retrospective study was 8.4% (14/167).4 These data were provided by leading Japanese hospitals carrying out ESD that have adequate experience in taking preventive measures for delayed bleeding similar to that of gastric ESD. Hoteya et al. analyzed various patient-, lesion-, and treatment-related factors and found that only endoscopic closure of the ulcer after duodenal ESD was significantly associated with a decreased incidence of delayed bleeding.3 In other words, the exposure of submucosal or muscle layer to the duodenal lumen is at risk of delayed bleeding. Digestion of the thin ulcer bed by direct exposure to pancreatic and bile juices has been speculated.7 Closure of the ulcer after duodenal ESD has also been reported as a preventive measure for delayed perforation8 which is a distinctive complication of duodenal ESD.4, 7 If successful closure of the ulcer were possible, the risk of delayed bleeding or perforation would be minimized, which would lead to earlier oral feeding and short-term admission. However, as Hoteya et al. also pointed out, endoscopic closure is sometimes impossible depending on the location and size of the ulcer, and scope maneuverability.3 Others report that conventional clips are so small that they might injure the ulcer bed, or that they are too small to close the ulcer, and that the grasping power is insufficient to keep the ulcer closed.8 Early dislocations of conventional clips are speculated as a factor in delayed perforation among cases that underwent endoscopic closure.4, 7 Therefore, newer procedures of endoscopic closure using over-the-scope clips8 or polyglycolic acid sheets9, 10 have been reported. Polyglycolic acid sheets are reported to remain on the ulcer bed for at least a week, which may theoretically cover the hazardous postoperative period of delayed bleeding and perforation.9, 10 Over-the-scope clips are large and characterized by their strong grasping and holding force that enables hemostasis of uncontrollable bleeding and successful closure of perforations.8 Both methods have been applied in a small number of cases only; however, they are promising procedures that may be an alternative when a conventional clip method cannot be applied. Long-term results of duodenal ESD are lacking; therefore, it is unknown whether ESD is more beneficial than EMR for duodenal neoplasms. However, the number of duodenal ESD is surely increasing like ESD in other parts of the GI tract. The particularly high rate of complications, as well as the demanding technique, should be realized. Management of ulcers after duodenal ESD to avoid delayed complications should be clarified by well-designed prospective trials. Meanwhile, endoscopic closure is the sole validated and affordable preventive measure for delayed bleeding.