P311 Microscopic inflammation and myenteric plexitis at the margin of resection do not predict endoscopic recurrence in patients with Crohn's disease after ileocolic resection
Boland K.*1, Stempak J.1, Weizman A.1, Nguyen G.1, Kennedy E.1, MacRae H.1, Cohen Z.1, Croitoru K.1, Conner J.2, Silverberg M.1
1Mount Sinai Hospital, Zane Cohen Center for Digestive Diseases, Toronto, Canada 2Mount Sinai Hospital, Department of Pathology, Toront, Canada
Studies have produced conflicting results regarding the predictive value of histological inflammation and myenteric plexitis at the margin to identify patients at risk of recurrence after resection for Crohn's Disease (CD). The aim of this study is to determine whether these features predict endoscopic recurrence after ileocolic resection (ICR).
Patients with CD referred for ICR with a primary anastomosis were enrolled in a prospective study at a tertiary centre. Clinical information and demographics were recorded. Hematoxylin and eosin stained slides from resection specimens were evaluated for grade of microscopic activity (None, focal, mild, moderate or severe) at proximal and distal margins, and the presence of submucosal plexitis. Gross inflammation at the margins was recorded. Post-operatively, patients underwent colonoscopy with mucosal biopsies at 3–6 months and 12–18 months post resection. Neo-terminal ileum Rutgeert's score > i2 determined recurrence. Bivariate analysis was performed with Fisher's exact test and relative risk calculated by Koopman score using Graphpad.
45 patients were enrolled in this study. Correcting for withdrawals, incomplete follow-up and unavailable specimens, 29 patients were included. Twenty-seven patients (93.1%) had at least 2 post-operative colonoscopies with a median follow-up interval of 18 months (4–144 months). The cumulative recurrence rate was 41.4% (12/29). Risk factors including age, disease phenotype and smoking status were not related to recurrence. Shorter time to first resection for CD (median 1 vs 8 years, p=0.017, Mann Whitney U test) and no post-operative anti-TNF therapy use (n=5/29 [0% with recurrence vs 23.5% without]; p=0.001) increased risk of recurrence over the total follow-up period. Patients on anti-TNF at first follow up were excluded from this analysis (n=4). Gross inflammation at the proximal margin was present in 25% (3/12) with and 15.4% (2/13) without recurrence (p=0.622). Neither presence nor degree of microscopic inflammation at the proximal or distal resection margins was associated with endoscopic recurrence at any time point (n=5/12 vs 6/13) p>0.9). We found no association between submucosal plexitis and risk of recurrence (33.3% in recurrence vs 23% without; p=0.67).
Independent of concurrent anti-TNF therapy, histological or gross inflammation at the proximal or distal resection margins at the time of resection did not predict early or subsequent endoscopic recurrence. In addition, myenteric plexitis did not predict disease recurrence. Confounding factors which may influence these results include cohort size and the median duration of follow up.