Impact of Perianal Inflammatory Lesions in Crohn's Disease Patients with Anorectal Cancer

Perianal inflammatory lesions (PILs), such as anal fistulas and perianal abscesses, are major complications of perianal Crohn's disease (CD). These lesions reflect inflammation status of CD and pose a risk of carcinogenesis. Their presence may be a risk factor for surgical complications and poor prognosis; however, their impact on CD patients with anorectal cancer is not well understood.

This nationwide multicenter observational study included patients with CD who underwent abdominoperineal resection or total pelvic exenteration for anorectal cancer. Patients with distant metastases were excluded. Data collected by the Japanese Society for Cancer of the Colon and Rectum from 43 participating hospitals between January 1983 and December 2020 were analyzed according to the presence or absence of PILs. Postoperative complications, overall survival, and relapse-free survival rates were compared between groups.

A total of 173 patients (135 with and 38 without PIL) were included. Postoperative complications were not significantly different between the patients with and without PILs (46.2% vs 45.9%, P=1.000). Five-year overall survival was 73.3% (95% confidence interval (CI) 48.8-87.4%) in patients without PILs, which was significantly higher than the 46.8% (95%CI 36.4-56.6%) in those with PILs (P=0.027). Five-year relapse-free survival was 52.5% (95% CI 30.8-70.3%) in patients without PILs, which was higher than the 40.2% (95%CI 30.6-49.5%) in those with PILs, without statistical significance (P=0.065).

In patients with CD and anorectal cancer, the presence of PILs did not increase the incidence of postoperative complications; however, it worsened prognosis.