In previous single center study, both modified cap-assisted endoscopic mucosal resection (mEMR-C) and endoscopic submucosal dissection (ESD) were reported to be effective for the treatment of small rectal neuroendocrine tumors (NETs) and mEMR-C was inferior to ESD for the treatment of small rectal NETs (≤10 mm), as it has shorter operation times and lower hospitalization costs. However, a multicenter randomized controlled trial is needed to prove the universality and generality of these findings.

Investigators aimed to conduct a muticenter randomized controlled trial to compare mEMR-C with ESD for the treatment of small rectal neuroendocrine tumors (NETs) in six tertiary hospitals in China.

Inclusion Criteria:

1. Age from 18 to 75 years;
2. With a high suspicion or evidence of rectal NET assessed using EUS or colonoscopy;
3. With tumor size ≤10 mm assessed by colonoscopy;
4. Plan to receive mEMR-C or ESD treatment and provide written informed consent;

Exclusion Criteria:

1. Unable to tolerate ESD or MEMR-C as assessed by the research team of each center;
2. Complicated with serious diseases such as malignant tumor, which may lead to shorter life expectancy, the research team considers that it is not suitable for inclusion in the study after comprehensive evaluation;
3. Rectal NET with lymph node metastasis or distant metastasis;
4. Received resection of rectal neuroendocrine tumor by other surgical procedures;
5. Multiple rectal neuroendocrine tumors;
6. Vulnerable groups such as pregnant women or patients with mental disorders;
7. Poor compliance, unable to cooperate with treatment.