What is the evidence that seton placement improves long-term outcomes in perianal CD compared with anti‑TNF therapy alone

What is known

- A 2016 systematic review/meta-analysis compared seton drainage and anti-TNF success rates but framed management as shifting toward medical therapy, not seton superiority. ¹ - Combined seton placement plus anti-TNF (infliximab) maintenance is the recurring intervention studied, with reported clinical advantages over single modalities. ^2,3 - A 2025 multicentre registry examined seton impact specifically in patients already on anti-TNF, and a published letter questioned its outcome measurement and interpretation. ^4,5

What is unknown / caveats

- 2025 registry on seton impact under anti-TNF drew a published rebuttal on outcome-measurement validity - No retrieved study directly randomizes seton vs anti-TNF monotherapy for long-term outcomes - Most evidence is retrospective/observational and evaluates combined therapy, not isolated modalities - Seton timing/removal remains an unsettled variable across studies - The retrieved corpus cannot isolate the independent long-term benefit of a seton from concurrent anti-TNF.

## References

1. de Groof EJ, Sahami S, Lucas C, Ponsioen CY, Bemelman WA, Buskens CJ. Treatment of perianal fistula in Crohn's disease: a systematic review and meta-analysis comparing seton drainage and anti-tumour necrosis factor treatment. Colorectal Dis. 2016;18(7):667-75. PMID: 26921847.

2. Tanaka S, Matsuo K, Sasaki T, Nakano M, Sakai K, Beppu R, Yamashita Y, Maeda K, Aoyagi K. Clinical advantages of combined seton placement and infliximab maintenance therapy for perianal fistulizing Crohn's disease: when and how were the seton drains removed?. Hepatogastroenterology. 2010;57(97):3-7. PMID: 20422862.

3. Horio Y, Uchino M, Tomoo Y, Nomura K, Nagano K, Kusunoki K, Kuwahara R, Kimura K, Kataoka K, Takagawa T, Ikeda M, Ikeuchi H. Timing of seton removal and clinical outcomes in perianal fistulizing Crohn's disease: A systematic review and meta-analysis. Colorectal Dis. 2026;28(4):e70449. PMID: 42003433.

4. McCurdy J, Munir J, Parlow S, Sambhi G, Reid J, Yanofsky R, Alenezi T, Meserve J, Yeh KH, Becker B, Lahijanian Z, Eddin AH, Mallick R, Ramsay T, Rosenfeld G, Bessissow A, Bessissow T, Jairath V, Bruining DH, Macdonald B, Singh S, Canadian IBD Research Consortium (CIRC). The Impact of Setons on Perianal Fistula Outcomes in Patients With Crohn's Disease Treated With Anti-TNF Therapy: A Multicentre Study. Aliment Pharmacol Ther. 2025;61(10):1671-1679. PMID: 40098436.

5. Liu D, Zhong B, Guo L. Letter: Re-Examining Seton Efficacy in Perianal Crohn's Disease-Considerations for Outcome Measurement and Clinical Interpretation. Aliment Pharmacol Ther. 2025;61(12):1969-1970. PMID: 40276844.

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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._