Crohn's disease-like reaction predicts favorable prognosis in colitis-associated colorectal cancer

Background: Idiopathic inflammatory bowel disease is associated with an increased risk of developing colorectal cancer. Colitis-associated colorectal cancer (CAC) has unique histomorphology features; however, whether histomorphology is predictive of survival in CAC, independent of overall clinical tumor stage, remains unknown. The aim of this study is to determine if clinicodemographics and tumor histomorphologic features are prognostic in patients with CAC. Methods: A cohort of CAC patients were identified from the Pathology Database at Cleveland Clinic; slides were reviewed and other relevant data were collected by retrospective review of medical records. Results: Univariate analysis demonstrated that poor differentiation, N stage (N1/N2 versus N0), M stage (M1 versus M0), Tumor, Node, Metastasis (TNM) stage (III/IV versus I/II), positive margin, and Crohn's-like reaction were significantly associated with both overall survival (OS) and progression-free survival (PFS) in CAC. Additionally, the presence of >2 tumor-infiltrating lymphocytes/high-power field was found to be significantly associated with longer PFS. Multivariate analysis confirmed that high TNM stage (III/IV versus I/II) was associated with shorter OS and PFS (hazard ratio 2.7, 95% confidence interval [CI]: 1.1-6.7, P = 0.04; 4.84 [95% CI: 2.0-11.5], P < 0.001, respectively), and positive margin status was associated with shorter OS (hazard ratio 4.0 [95% CI: 1.0-15.7], P = 0.05), whereas the presence of Crohn's-like reaction was associated with longer OS and PFS (hazard ratio 0.3 [95% CI: 0.12-0.79], P = 0.02; 0.25 [95% CI: 0.11-0.58], P = 0.001, respectively). Conclusions: In CAC, high tumor clinical stage and positive margin predict worse survival but Crohn's disease-like reaction is associated with longer OS and PFS.