Pongprasobchai N, Kositamongkol C, Mepramoon E, Phisalprapa P. Incidence of colorectal cancer and advanced polyps by post-polypectomy surveillance interval: Real-world evidence from Thailand. World J Gastroenterol 2026; 32(47): 122370 [DOI: 10.3748/wjg.122370]
Corresponding Author of This Article
Pochamana Phisalprapa, MD, PhD, Associate Professor, Lecturer, Senior Researcher, Division of Ambulatory Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Siriraj, Bangkok Noi, Bangkok 10700, Krung Thep Maha Nakhon, Thailand. pochamana.phi@mahidol.ac.th
Research Domain of This Article
Gastroenterology & Hepatology
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research-article
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Pongprasobchai N, Kositamongkol C, Mepramoon E, Phisalprapa P. Incidence of colorectal cancer and advanced polyps by post-polypectomy surveillance interval: Real-world evidence from Thailand. World J Gastroenterol 2026; 32(47): 122370 [DOI: 10.3748/wjg.122370]
Napat Pongprasobchai, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Krung Thep Maha Nakhon, Thailand
Chayanis Kositamongkol, Euarat Mepramoon, Pochamana Phisalprapa, Division of Ambulatory Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Krung Thep Maha Nakhon, Thailand
Author contributions: Pongprasobchai N, Kositamongkol C and Phisalprapa P designed the study; Pongprasobchai N, Kositamongkol C and Mepramoon E collected the data; Pongprasobchai N, Kositamongkol C and Phisalprapa P analyzed and interpreted the data; Pongprasobchai N, Kositamongkol C and Phisalprapa P performed statistical analysis; Phisalprapa P supervised the study; Mepramoon E served as administrator and provided technical, or material support; Pongprasobchai N and Kositamongkol C performed the manuscript preparation; Pongprasobchai N, Kositamongkol C, Mepramoon E and Phisalprapa P participated in the review and editing; All authors have read and approved the final manuscript.
AI contribution statement: Portions of this manuscript were edited using AI tools (Perplexity) solely for language refinement. The authors carefully reviewed and verified all AI-assisted outputs and take full responsibility for the scientific content of the manuscript.
Institutional review board statement: The study was reviewed and approved by the institutional review board at the Faculty of Medicine Siriraj Hospital, Mahidol University (Certificate of Approval number: Si 104/2024).
Informed consent statement: The informed consent was waived because of the retrospective nature of the study.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Data sharing statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.
Corresponding author: Pochamana Phisalprapa, MD, PhD, Associate Professor, Lecturer, Senior Researcher, Division of Ambulatory Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Siriraj, Bangkok Noi, Bangkok 10700, Krung Thep Maha Nakhon, Thailand. pochamana.phi@mahidol.ac.th
Received: April 17, 2026 Revised: May 26, 2026 Accepted: July 10, 2026 Published online: December 21, 2026 Processing time: 193 Days and 22.6 Hours
Abstract
BACKGROUND
Globally, colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related mortality. Given the limited colonoscopy capacity in low- and middle-income countries, it is essential to identify surveillance intervals that maintain clinically acceptable CRC detection rates while using resources efficiently.
AIM
To examine the incidence of CRC and advanced polyps across different post-polypectomy surveillance intervals.
METHODS
Medical records of post-polypectomy patients at Siriraj Hospital (June 2011 to October 2023) were retrospectively reviewed. Patients were classified into low-risk and high-risk groups based on baseline colonoscopy findings, and the incidence of CRC and advanced polyps was calculated and compared across early, usual, and late surveillance intervals. Odds ratios were estimated using logistic regression, and survival analysis was performed.
RESULTS
Among 2875 included patients, 41.63% were low-risk. CRC incidence was 0.70% (2.04 cases per 1000 patient-years), whereas the incidence of CRC and advanced polyps was 12.52% (36.67 cases per 1000 patient-years). The incidence proportions of CRC and advanced polyps for early, usual, and late intervals in the high-risk group were 15.39%, 17.17%, and 17.42%, respectively. These proportions in the low-risk group were 5.63%, 7.19%, and 9.63%, respectively. The odds ratio for CRC and advanced polyps in late vs early intervals was 1.79 (95% confidence interval: 1.12-2.85; P = 0.015) in the low-risk group. Event-free survival for CRC and advanced polyps fell below 80% when the surveillance interval exceeded 8 years in the low-risk group.
CONCLUSION
Tailoring surveillance intervals improves outcomes and resource allocation. High-risk patients require surveillance every 2-3 years; low-risk patients may safely extend intervals to 7-8 years unless new symptoms arise.
Core Tip: This 12-year retrospective cohort study provided real-world evidence to optimize post-polypectomy surveillance in resource-limited settings. Analyzing 2875 Thai patients, we found that high-risk patients require surveillance every 2-3 years to minimize colorectal cancer risk. While, low-risk patients may safely extend surveillance intervals to 7-8 years unless new symptoms arise. Tailoring surveillance by risk group offers a viable strategy to maximize endoscopic capacity without compromising patient safety, providing a practical framework for low- and middle-income countries to improve colorectal cancer prevention outcomes.
