Utility of underwater endoscopic mucosal resection combined with a protruding anchor by saline injection for superficial non-ampullary duodenal tumors: a retrospective study in Japan.

Background: Underwater endoscopic mucosal resection (UEMR) is the standard resection method for superficial non-ampullary duodenal tumors (SNADETs). We developed a novel UEMR technique that creates an anchor by protruding the distal fold with a saline injection (UEMR-A). The aim of this study was to clarify the usefulness of UEMR-A compared to conventional UEMR (UEMR-C).

Methods: This retrospective observational study included patients who underwent UEMR for SNADETs.

Results: A total of 141 patients were included and divided into UEMR-A (n=54) and UEMR-C (n=87) groups. Lesion resection was performed significantly more frequently by an expert endoscopist in the UEMR-C group compared to the UEMR-A group (p<0.001). The procedure time for UEMR-A was significantly shorter than that for UEMR-C (p=0.018), despite the additional time required for submucosal injection. The R0 resection rate was significantly higher in the UEMR-A group than in the UEMR-C group (p=0.004). The horizontal margins were significantly clearer in the UEMR-A group than in the UEMR-C group (p=0.018). Multivariate analysis revealed that the use of UEMR-A was the only significant positive factor for R0 resection.

Conclusions: The UEMR-A technique for SNADETs appears to improve R0 resection rates and reduce procedure times compared to the UEMR-C technique.