Is salvage treatment necessary after incomplete resection of rectal neuroendocrine tumors: A systematic review and meta-analysis

doi:10.3748/wjg.v32.i3.113452

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World Journal of Gastroenterology

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Meta-Analysis

World J Gastroenterol. Jan 21, 2026; 32(3): 113452
Published online Jan 21, 2026. doi: 10.3748/wjg.v32.i3.113452

Is salvage treatment necessary after incomplete resection of rectal neuroendocrine tumors: A systematic review and meta-analysis

Jae Hyun Kim, Jung Won Lee, Hyun Jung Kim, Seung Min Hong, Seun Ja Park

Jae Hyun Kim, Seun Ja Park, Department of Internal Medicine, Kosin University College of Medicine, Busan 49267, South Korea

Jung Won Lee, Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon 51353, Gyeongsangnam-do, South Korea

Hyun Jung Kim, Cochrane Korea and Institute for Evidence-Based Medicine, Korea University College of Medicine, Seoul 02841, South Korea

Seung Min Hong, Department of Internal Medicine, Pusan National University School of Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan 49241, South Korea

Author contributions: Kim JH and Park SJ conceptualized and designed the study; Kim JH and Lee JW collected and analyzed the data; Kim HJ supervised the systematic review process and statistical methodology; Hong SM provided critical revisions and expert review; Kim JH drafted the manuscript; Park SJ critically revised the final version of the manuscript; all authors reviewed and approved the final manuscript.

Conflict-of-interest statement: The authors declare that they have no conflict of interest.

PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.

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: Seun Ja Park, MD, Professor, Department of Internal Medicine, Kosin University College of Medicine, Gamcheonro 262, Seogu, Busan 49267, South Korea. parksj6406@daum.net

Received: August 26, 2025
Revised: October 23, 2025
Accepted: December 5, 2025
Published online: January 21, 2026
Processing time: 143 Days and 21.4 Hours

Abstract

BACKGROUND

Incomplete resection of rectal neuroendocrine tumors (NETs), defined by positive or indeterminate margins or lymphovascular invasion, raises concerns regarding residual disease and recurrence. However, the benefits of salvage treatment in these cases remain unclear.

AIM

To evaluate the oncologic impact of salvage treatment compared with observation after incomplete endoscopic resection of rectal NETs through a systematic review and meta-analysis.

METHODS

We conducted a systematic review and meta-analysis in accordance with the preferred reporting items for systematic reviews and meta-analyses guidelines. MEDLINE, EMBASE, and the Cochrane Library were searched from their inception until May 2025. Eligible studies included patients with incompletely resected rectal NETs managed with salvage treatment or observation, reporting outcomes of residual tumors or recurrence. Pooled estimates were calculated using random-effects models with Hartung-Knapp adjustments.

RESULTS

Thirty-four studies with 2279 cases of incomplete endoscopic resection met the inclusion criteria. The incomplete resection rates differed markedly according to the initial resection method (17 studies): 73.1% for cold snare polypectomy, 29.8% for conventional endoscopic mucosal resection (EMR), 28.4% for modified EMR, and 14.7% for endoscopic submucosal dissection. Among the 19 studies that evaluated salvage treatment, the pooled residual tumor rate was 25.0% [95% confidence interval (CI): 12.0%-40.0%]. The crude recurrence rates from 31 studies favored salvage treatment over observation (0.96% vs 2.96%, P = 0.003). However, a meta-analysis of nine comparative studies found no statistically significant difference in recurrence risk (odds ratio = 0.89; 95%CI: 0.40-2.02).

CONCLUSION

Given the relatively high residual tumor rate and low incidence of recurrence, salvage treatment may be justified as both a diagnostic and therapeutic approach after incomplete resection of rectal NETs. Although its benefits in preventing recurrence remain unclear, clinical decisions should be individualized, as these findings are based on low-certainty evidence.

Keywords: Rectum; Neuroendocrine tumors; Residual neoplasm; Salvage therapy; Observation

Core Tip: Incomplete resection of rectal neuroendocrine tumors raises concern for residual disease and recurrence, yet the optimal management remains debated. In this systematic review and meta-analysis of 34 studies, residual tumors were identified on salvage pathology in about 25% of cases, whereas recurrence was rare in both salvage and observation groups. Although crude data suggested fewer recurrences with salvage treatment, comparative meta-analysis showed no significant difference. These findings highlight salvage resection as a diagnostic and therapeutic option, but its routine use for recurrence prevention is uncertain. Clinical decisions should be individualized.