Journal of surgical oncology
July 12, 2026 · via Europe PMC
Malignant Transformation of Perianal Fistulas: A Systematic Review of the Literature.
Regmi P, Regmi SM, Sah VP, +9 more, Gupta RK.
AI summary — for doctors, generated from the abstract only
A systematic review of 172 cases found that malignant transformation of chronic perianal fistulas (most often associated with Crohn's disease) is typically diagnosed after decades of fistula duration, usually treated with abdominoperineal resection, and carries a substantial risk of recurrence and death.
What was studied
A systematic review and single-arm meta-analysis of 11 retrospective studies (172 patients) with malignant transformation of perianal fistulas, examining clinicopathologic characteristics and treatment outcomes using pooled data from PubMed, Scopus, and Web of Knowledge.
Key findings
- 172 patients (135 male, 37 female) were included; mean age was 56.89 years, with pain as the most frequent presenting complaint.
- Mean duration of Crohn's disease was 30.61 years, and mean fistula duration before cancer diagnosis was 17.92 years.
- Abdominoperineal resection was the most common surgical procedure, and adenocarcinoma was the most common histologic subtype.
- Over a mean follow-up of 40.56 months, 20.16% of patients had recurrence and 35.62% died.
Clinical relevance
The findings suggest that very long-standing perianal fistulas (particularly in Crohn's disease) carry a small but serious risk of malignant transformation, which may be relevant to maintaining a high index of suspicion and considering biopsy in patients with chronic, long-duration fistulas, especially with changing symptoms.
Who should care
Limitations
This is a pooled analysis of retrospective, non-comparative case series without a control group, so true incidence and risk factors cannot be firmly established; the rarity of this condition limits the certainty of the prognostic estimates, and the authors themselves note the pathophysiology and prognostic factors remain poorly understood.
Malignant transformation of chronic perianal fistulas is rare but carries substantial recurrence and mortality risk, typically arising after many years of fistula duration.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Malignant transformation of a perianal fistula is rare, predominantly associated with chronic fistula. Carcinogenesis is presumably initiated by chronic inflammation, and its mechanism is not clearly understood. We aimed to study the clinicopathologic characteristics and treatment outcomes of patients with malignant perianal fistula. A systematic literature search was performed on the electronic databases of PubMed, Scopus, and Web of Knowledge. A single-arm meta-analysis of non-comparative studies was performed using OpenMeta[Analyst] software. Eleven retrospective studies, including 172 patients (M: 135/F: 37), were included. The mean age of the patients was 56.89 years, and the most frequent presenting complaint was pain. The estimated mean duration of Crohn's disease (CD) was 30.61 years, and the mean duration of fistula before diagnosis was 17.92 years. The most commonly performed procedure was abdominoperineal resection (APR) and the most common histopathological subtype was adenocarcinoma. During the mean follow-up time of 40.56 months, 20.16% of patients had recurrence, and 35.62% of patients died. The pathophysiology of fistula-associated cancer is not well known, has diagnostic challenges, and the literature is sparse in predicting prognosis.
DOI
10.1002/jso.70321
PMID
42437515
PMCID
PMC13575602
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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