Underwater Endoscopic Mucosal Resection Versus Endoscopic Submucosal Dissection for the Treatment of Small Rectal Neuroendocrine Tumors

Inclusion Criteria:

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

Exclusion Criteria:

1. Unable to tolerate ESD or UEMR as assessed by the research team;
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.