Endoscopic submucosal resection with a ligation device (ESMR-L) achieved noninferior histologically complete resection compared with endoscopic submucosal dissection (ESD) for small rectal neuroendocrine tumors (NETs), with shorter procedure time, reduced hospital stay and lower costs, according to data presented at Digestive Disease Week® (DDW) 2026 in Chicago.
In a multicenter Japanese trial, R0 resection was achieved in 97% of patients undergoing ESMR-L versus 92% with ESD, while mean procedure time fell from 28.0 minutes to 5.2 minutes and mean procedural cost dropped from 51,102 Japanese yen to 24,382 yen.
Trial design and patient population
Jun Arimoto, MD, PhD, of the Department of Gastroenterology at Omori Red Cross Hospital in Tokyo, presented the findings from a prospective, open-label, multicenter, noninferiority randomized controlled trial conducted across 32 institutions in Japan, comparing ESMR-L with ESD in patients with endoscopically diagnosed rectal NETs measuring 10 mm or less. Patients were stratified by institution and endoscopist expertise, defined as having performed more than 40 prior colorectal ESD procedures.
The primary endpoint was the rate of en bloc resection with histologically tumor-free margins (R0 resection). Secondary endpoints included en bloc resection rate, procedure time, hospital stay, devices and agents cost, and adverse events.
The study was powered based on expected R0 resection rates of 95% in both groups, with an 8% noninferiority margin and adjustment for dropout. A total of 60 expert and 33 nonexpert endoscopists participated.
Among 266 enrolled patients, 257 were included in the primary analysis after exclusion of non-neoplastic lesions, with 130 assigned to ESD and 127 to ESMR-L. Baseline characteristics, including age, sex, performance status, antithrombotic use and lesion location, were comparable between groups, with a mean tumor diameter of 5.4 mm.
Resection outcomes
R0 resection was achieved in 92% of patients in the ESD group and 97% in the ESMR-L group, meeting the predefined noninferiority margin. En bloc resection was achieved in all patients in both groups.
Subgroup analyses stratified by endoscopist expertise showed consistent findings favoring ESMR-L. Among expert endoscopists, the difference in R0 resection rates was 3.2 percentage points, while among nonexpert endoscopists, the difference was 8 percentage points.
Procedural efficiency and safety
Secondary outcomes favored ESMR-L across procedural and resource metrics. Mean procedure time was 28.0 minutes with ESD versus 5.2 minutes with ESMR-L. Mean hospital stay was 4.4 days versus 3.4 days, and mean procedural cost was 51,102 Japanese yen versus 24,382 yen.
Adverse events were infrequent and comparable between groups. Postoperative bleeding occurred in three (2%) versus five (4%) patients, with no perforations observed.
Clinical implications and future research
“ESMR-L was noninferior to ESD for achieving histologically complete resection of rectal NETs measuring 10 mm or less, while requiring substantially shorter procedure time and lower procedural cost,” Dr. Arimoto said. “The findings suggest that ESMR-L may represent a practical first-line endoscopic treatment option for small rectal NETs, particularly in settings where advanced colorectal ESD expertise is limited.”
Dr. Arimoto also noted that use of ESMR-L may simplify endoscopic management of small rectal NETs, reduce procedure-related resource utilization, and facilitate broader access to curative endoscopic treatment without compromising resection quality.
The trial was conducted exclusively in Japan and evaluated a single ligation device, and long-term outcomes data on local recurrence and metastasis are not yet available.
Regarding cautions and next steps, Dr. Arimoto said “long-term follow-up data regarding local recurrence and metastasis are needed, and further studies are also warranted to evaluate the applicability of ESMR-L outside Japan and with other ligation devices.”
Dr. Arimoto and the other authors of the study reported having no disclosures
DDW is AGA's annual meeting, jointly sponsored by AGA, AASLD, ASGE, and SSAT. Learn more at ddw.org.