Endoscopic Resection of Rectal Neuroendocrine Tumors: How Deep Should We Go?

Area of Science:

• Gastroenterology
• Surgical Oncology
• Endoscopic Surgery

Background:

• Small rectal neuroendocrine tumors (r-NETs) are increasingly found during colorectal cancer screening.
• Optimal endoscopic resection depth for these lesions is unclear.
• Endoscopic submucosal dissection (ESD) is standard, but endoscopic intermuscular dissection (EID) may offer deeper resection for complex cases.

Purpose of the Study:

• To evaluate the safety and efficacy of EID compared to ESD for r-NETs.
• To determine if EID achieves reliable deep-margin clearance.
• To assess if EID is suitable for fibrotic or recurrent r-NETs.

Main Methods:

• Retrospective review of 42 patients with r-NETs treated between 2018-2025.
• 32 primary lesions treated with ESD, 10 lesions/scars treated with EID.
• Primary outcomes: en bloc and R0 resection; Secondary outcomes: procedure time, adverse events, length of stay.

Main Results:

• All cases achieved en bloc resection.
• R0 resection confirmed in all 26 primary lesions.
• EID successfully resected 2 recurrent NETs (grade 1) with R0 margins.
• No major adverse events; minor bleeding in 5 patients.
• Similar lesion size and procedure time between ESD and EID groups.

Conclusions:

• Both ESD and EID are safe and effective for r-NETs ≤20 mm.
• EID shows promise for fibrotic or recurrent r-NETs.
• Further prospective multicenter studies are needed to confirm the tailored use of EID.