In patients with UC of 15 years' duration with moderate activity and no dysplasia, is mesalamine chemoprevention or adding a thiopurine preferred for CRC risk reduction
What is known
- Guidelines (ECCO, BSG, Japanese Society of Gastroenterology) recommend 5-ASA for chemoprevention; the recommendation was strong but evidence moderate-to-low quality. 1,2 - ECCO states there is insufficient evidence to recommend for or against thiopurine chemoprevention. 1,2 - In the CESAME cohort, thiopurines reduced CRC/high-grade dysplasia risk in long-term extensive colitis (HR 0.28), but were linked to increased lymphoproliferative malignancy. 2 - Thiopurine protective effects vary by region and disease type, with no significant effect in some meta-analyses and case-control studies. 2–4
What is unknown / caveats
- Thiopurine studies show protection in some cohorts but no effect in several meta-analyses/case-control studies - One 5-ASA pooled analysis showed protection, a later nonreferral systematic review did not - No head-to-head mesalamine vs thiopurine comparison in the excerpts - Chemoprevention data are observational; an RCT is considered unfeasible/unethical - Excerpts do not address combining or sequencing the two agents - The excerpts do not compare the two agents directly, so relative preference for CRC prevention in this patient cannot be determined.
## References
1. Magro F, Gionchetti P, Eliakim R, Ardizzone S, Armuzzi A, Barreiro-de Acosta M, Burisch J, Gecse KB, Hart AL, Hindryckx P, Langner C, Limdi JK, Pellino G, Zagórowicz E, Raine T, Harbord M, Rieder F, European Crohn’s and Colitis Organisation [ECCO]. Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 1: Definitions, Diagnosis, Extra-intestinal Manifestations, Pregnancy, Cancer Surveillance, Surgery, and Ileo-anal Pouch Disorders. J Crohns Colitis. 2017;11:649-670. PMID: 28158501.
2. Hsiao SW, Yen HH, Chen YY. Chemoprevention of Colitis-Associated Dysplasia or Cancer in Inflammatory Bowel Disease. Gut Liver. 2022. PMID: 35670121.
3. Dan WY, Zhou GZ, Peng LH, Pan F. Update and latest advances in mechanisms and management of colitis-associated colorectal cancer. World J Gastrointest Oncol. 2023;15(8):1317-1331. PMID: 37663937.
4. Sengupta, Neil, Yee, Eric, Feuerstein, Joseph D. Colorectal Cancer Screening in Inflammatory Bowel Disease. Dig Dis Sci. 2016;61:980-9. PMID: 26646250.
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⚠ Required context not in this corpus (moderate). SCENIC consensus (Laine 2015, PMID 25708752): dysplasia surveillance in colonic IBD uses high-definition colonoscopy with chromoendoscopy and TARGETED biopsy of visible lesions, and a completely endoscopically resected visible dysplastic lesion is followed by surveillance rather than reflex colectomy.
_Why this matters:_ Advising colectomy for an endoscopically resectable visible dysplastic lesion, or describing random-biopsy-only surveillance as current practice, can commit a patient to an avoidable proctocolectomy.
_Added by the landmark interlock. This corpus is surgical in scope and cannot admit the source paper (PMID 25708752). Not generated by the RAG._
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_Draft, generated by the IBDology RAG and not yet clinician-reviewed. Answers are grounded in the retrieved literature listed above; a high faithfulness score means the answer matches its sources, not that the sources are correct._
Reviewer notes