June 15, 2021
Which patients with perianal fistulas will develop a local malignancy?
Clinicians managing Crohn’s disease should remain vigilant for the rare phenomenon of malignancy in perianal fistulas, particularly when disease is both complicated and chronic.
Palmieri C, Müller G, Kroesen AJ, et al. Perianal fistula-associated carcinoma in Crohn´s disease: a multicenter retrospective case control study. J Crohn’s Colitis. Epub ahead of print March 27, 2021; https://doi.org/10.1093/ecco-jcc/jjab057
In this retrospective case-control study, researchers at four hospitals in Germany analyzed data from 40 patients with Crohn’s disease (CD) who developed perianal fistula-related cancer and 40 randomly selected patients with CD and perianal fistulas but no related cancer. One prior study estimated that 0.8% of perianal fistulas develop carcinomas.
The current authors found that 82.5% of fistula-related cancers were adenocarcinomas, while the remainder were squamous cell carcinomas. Those with fistula-related cancers had been diagnosed with CD at an average 23 years of age, compared to an average of 27 years of age for those without cancer (p=0.04). The duration of CD was also longer among those with a fistula-related cancer (average 26 vs. 20 years; p=0.006).
Patients with fistula-related cancer were more likely to have a complex fistula (95% vs. 72.5%; p=0.006), chronic fistula activity (77.5% vs. 50%; p=0.01) and transsphincteric or intersphincteric involvement (87.5% vs. 67.5%; p=0.032).
Additionally, those with fistula-related cancer were more likely to have post-operative presentation (80% vs. 50%; p=0.005) and less likely to have had perianal pain (42.5% vs. 87.5%; p<0.001) leading to diagnosis.
The mean overall and progression-free survival rates were 45 months and 31.5 months, respectively, for those with fistula-related cancers. Multivariate analyses found several predictors of death during follow-up, the length of which was not specified in the publication. These included squamous cell carcinoma (Hazard Ratio [HR]: 9.45 vs. adenocarcinoma; 95% Confidence Interval [CI], 1.4–64; p=0.021), metastatic disease (HR: 36.65; 95% CI, 4.06–330.65; p=0.001) and positive surgical margins (HR: 6.75; 95% CI, 1.67–27.26; p=0.007).
Study Design: Retrospective case-control
Level of Evidence: 2b