Current status of endoscopic resection for small rectal neuroendocrine tumors

Table 1 Summary of resection techniques and recommendations for rectal neuroendocrine tumor less than 10 mm

Ref.	Endoscopic option	Strategy after R1 resection	Strategy after R0 resection with risk factors	General follow-up recommendations
French intergroup, 2020[17]	EMRL/EMRC/ESD	Consider salvage resection	Surgical resection with lymphadenectomy	No follow-up required for rNETs that are G1, < 10 mm, T1 and R0 after the initial resection. For others, regular endoscopic examination and abdominal/pelvic MRI
JNETS, 2021[64]	Not specified	Surgery	Surgery for rNETs that are > 1 cm or G2; MP invasion; or suspected local LNM	Not specified
ESGE, 2022[56]	mEMR	Repeat endoscopy at 3-6 m. Salvage resection with confirmed residue disease in expert centers	Annual endoscopy as well as imaging modalities	No follow-up required for rNET that are < 10 mm, G1-G2, no MP invasion, and no LNM
ENETS, 2023[13]	mEMR/ESD/EFR	Watch and wait after discussion with patient if negative EUS, MRI and repeat biopsy. Salvage endoscopic resection or TAMIS	For rectal NET G1 L1 or V1 or G2/G3 ≤ 10 mm, 6 monthly abdominopelvic MRI and yearly sigmoidoscopy for at least 5 years. 68Ga-SSR-PET/CT initially and after 12 months	No follow-up for a rectal NET G1 L0 V0 ≤ 10 mm. After R1 resection without a second endoscopic resection, endoscopy and EUS or MRI 12 monthly for at least 5 years is recommended
Italian, 2024[33]	mEMR (EMRC preferred) or ESD	Watch and wait may be considered after patient consultation. Salvage resection with EMR > ESD > EFR or TAMIS	Not specified	Not specified
NCCN, 2025[122]	Not specified	Endoscopy at 6-12 m to assess for residue disease. For patients with residual disease, rectal MRI or EUS should be performed before TEM/ER	Not specified	No follow-up

R0 resection: Complete resection; R1 resection: Incomplete resection; EMRL: Endoscopic submucosal resection with a ligation device; EMRC: Cap-assisted endoscopic submucosal resection; ESD: Endoscopic submucosal dissection; rNET: Rectal neuroendocrine tumor; MRI: Magnetic resonance imaging; JNETS: Japanese Neuroendocrine Tumor Society; MP: Muscularis propria; LNM: Lymph node metastasis; ESGE: European Society of Gastrointestinal Endoscopy; mEMR: Modified endoscopic submucosal resection; EFR: Endoscopic full-thickness resection; EUS: Endoscopic ultrasound; TAMIS: Transanal minimally invasive surgery; NET: Neuroendocrine tumor; 68Ga-SSR-PET/CT: Gallium-68-somatostatin receptor-positron emission tomography/computed tomography; EMR: Endoscopic submucosal resection; NCCN: National Comprehensive Cancer Network; TEM: Transanal endoscopic microsurgery; ER: Endoscopic resection.