Kim M, Kim Y, Kim JE, Hong SN, Chang DK, Kim YH, Kim ER. Long-term outcomes of endoscopic resection of 1-1.5 cm sized grade 1 rectal neuroendocrine tumor: A retrospective study. World J Gastroenterol 2025; 31(36): 109846 [DOI: 10.3748/wjg.v31.i36.109846]
Corresponding Author of This Article
Eun Ran Kim, MD, PhD, Department of Medicine, Samsung Medical Center, 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea. er.kim@samsung.com
Research Domain of This Article
Gastroenterology & Hepatology
Article-Type of This Article
Retrospective Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Gastroenterol. Sep 28, 2025; 31(36): 109846 Published online Sep 28, 2025. doi: 10.3748/wjg.v31.i36.109846
Long-term outcomes of endoscopic resection of 1-1.5 cm sized grade 1 rectal neuroendocrine tumor: A retrospective study
Minjee Kim, Yuwon Kim, Ji Eun Kim, Sung Noh Hong, Dong Kyung Chang, Young-Ho Kim, Eun Ran Kim
Minjee Kim, Ji Eun Kim, Sung Noh Hong, Dong Kyung Chang, Young-Ho Kim, Eun Ran Kim, Department of Medicine, Samsung Medical Center, Seoul 06351, South Korea
Yuwon Kim, Biomedical Statistics Center, Samsung Medical Center, Seoul 06351, South Korea
Author contributions: Kim M, Kim Y, and Kim ER contributed to data analysis and interpretation; Kim M and Kim ER contributed to study design, data acquisition, and final draft of the paper; Kim JE, Hong SN, Chang DK, and Kim YH critically revised the manuscript for important intellectual content. All the authors have read and approved the final manuscript.
Institutional review board statement: The study protocol was reviewed and approved by the Institutional Review Board of Samsung Medical Center (Approval No. SMC 2024-10-073-001). This study was conducted by the principles of the Declaration of Helsinki.
Informed consent statement: Information was only used if patients consented to electronical medical record access. The board exempted informed consent because all data were analyzed anonymously.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The data underlying this article cannot be shared publicly due to the privacy of individuals that participated in the study. The data will be shared on reasonable request to the corresponding author.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Eun Ran Kim, MD, PhD, Department of Medicine, Samsung Medical Center, 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea. er.kim@samsung.com
Received: May 30, 2025 Revised: June 30, 2025 Accepted: August 26, 2025 Published online: September 28, 2025 Processing time: 114 Days and 1.8 Hours
Abstract
BACKGROUND
Rectal neuroendocrine tumors (NETs) smaller than 10 mm and well-differentiated tumors are generally considered to have a low risk of lymph node and distant metastasis, making them suitable for endoscopic resection. In contrast, tumors ≥ 20 mm in size typically require surgical resection. However, the optimal management of intermediate-sized (10-15 mm) rectal NETs remains controversial.
AIM
To compare the clinical outcomes of endoscopic resection of rectal NETs < 1 cm and those 1-1.5 cm in size.
METHODS
A retrospective study was conducted on 1056 patients with rectal NETs treated at the Samsung Medical Center between January 2005 and June 2021. After propensity score matching (1:10) for age, sex, and type of endoscopic resection, 225 patients with tumors < 1 cm in size and 27 patients with tumors 1-1.5 cm in size were analyzed.
RESULTS
Surgical resection was more frequent in the 1-1.5 cm group (37.2%) than in the < 1 cm group (10.7%) (P < 0.01). Endoscopic submucosal dissection was also more commonly performed in the 1-1.5 cm group (48.1% vs 18.5%, P < 0.01). Negative resection margins were achieved in 97.2% of the patients, with no significant difference between the groups (P = 0.22). No lymphovascular invasion was observed. During a median follow-up of 54 months, no recurrence occurred in the 1-1.5 cm group, while one case of metachronous recurrence was noted in the < 1 cm group (P = 1.00). There was no significant difference in recurrence-free survival (P = 0.48).
CONCLUSION
Endoscopic resection of 1-1.5 cm grade 1 rectal NETs yielded comparable outcomes to those < 1 cm in size, suggesting its feasibility as a treatment.
Core Tip: This study demonstrated that endoscopic resection for 1-1.5 cm well-differentiated rectal neuroendocrine tumors offers clinical outcomes comparable to those for tumors < 1 cm, with high rates of negative margins and no observed recurrence in the intermediate-size group. These findings support the feasibility of endoscopic treatment for 1-1.5 cm rectal neuroendocrine tumors, address a key area of clinical uncertainty, and potentially expand the role of minimally invasive management in this subgroup.
