P0396 Combined clinical and histopathological risk stratification for prediction of (severe) endoscopic postoperative recurrence in patients with Crohn’s disease after ileocolic resection
Authors: Bak M , Oudijk L , Ooms A , Beelen E , van der Bilt J , Romberg-Camps M , Dijkstra G , Duijvestein M , van der Marel S , Stassen L , Maljaars J , Buskens C , Lange J , Kats-Ugurlu G , Jansen S , Jharap B , Horjus C , van Schaik F , West R , de Boer N , van der Woude J , Parikh K , van Ruler O , Doukas M , de Vries A 
Published: January 2025

Abstract

Background
The predictive value of histopathologic features of the intestinal resection specimen for the risk of Crohn’s disease (CD) recurrence after ileocolic (re-)resection (ICR) remains a matter of debate. Therefore, this study assessed the association of histopathological features in the resection specimen of CD patients with (severe) endoscopic postoperative recurrence (ePOR) in a large prospective, multicenter cohort study.

Methods
CD patients (≥16 years) scheduled for ICR were included from an ongoing prospective cohort study. Outcome measures were ePOR (modified Rutgeerts’ score ≥i2b) and severe ePOR (≥i3) at six months postoperatively. Proposed histopathological risk factors for postoperative recurrence (active inflammation, de novo granulomas, myenteric and submucosal plexitis, and transmural inflammation) were assessed in the ileal and colonic resection margins by expert pathologists blinded for outcomes. In addition, presence of chronic inflammatory cells, abceding inflammation, fat necrosis, fibrosis and de novo was assessed in the mesentery/mesocolon. Logistic regression was performed and ROC curves were delineated to explore the association and accuracy of histopathology with (severe) ePOR.

Results
In total, 293 patients were eligible for inclusion. Baseline characteristics are displayed in Table 1. Only moderate to severe inflammation at the ileal resection margin (OR 2.5; 95%CI 1.1-5.6) was associated with ePOR in multivariable analysis. Significant higher rates of ePOR were observed in patients with active inflammation at the ileal or colonic margin (p=0.01; p=0.03), submucosal plexitis at the ileal margin (p=0.04) and transmural inflammation (p&lt;0.01). Transmural inflammation or submucosal plexitis at the ileal margin (p=0.02; p=0.01) and mesenteric granulomas (p&lt;0.01) were significantly higher in patients with severe ePOR.
Area under the curve (AUC) for individual histopathological risk factors varied between 0.53-0.58 for ePOR (active inflammation at the resection margins, submucosal plexitis and transmural inflammation) and 0.69-0.71 for severe ePOR (submucosal plexitis, transmural inflammation and mesenteric granulomas)(Figure 1). Clinical risk factors alone (active smoking and postoperative prophylactic medication) had an AUC of 0.66 and 0.74 for ePOR and severe ePOR. Combined histopathological and clinical risk stratification increased the AUC up to 0.71 for ePOR and up to 0.79 for severe ePOR.

Conclusion
Only moderate to severe inflammation at the ileal margin was independently associated with ePOR. A combined approach of clinical risk stratification and assessment of histopathological features in the resection specimen provides an adequate predictive value for (severe) ePOR after ICR in patients with CD.