P657 Backwash ileitis not influences the risk of the pouchitis, but can increase the risk of the pouch dysplasia

Abstract Background Backwash ileitis (BI) is the term given to endoscopic and/or histological inflammation that extends from the caecum continuously into the terminal ileum in a ulcerative colitis (UC) patient with extensive colitis. The opinion about the role of the BI in patients after restorative proctocolectomy, as a risk factor for pouchitis development is very controversial. Most author’s present the results showing no influence of the BI on the pouchitis occurrence, both acute and chronic. The data about correlation between BI and pouch dysplasia and neoplasia are incidental and not clear. Methods The study group consisted of 276 patients with ulcerative colitis after restorative proctocolectomy performed between the years 1984 and 2009. Within this group there were 143 women and 133 men with a mean age of 33.4 ± 12.1 years. The clinical data from screening assessments made in 2014–2018 was analysed. The flexible or rigid endoscopy was done in all patients. Dysplasia and neoplasia were recognised on the basis of standard pathological examinations of the pouch mucosa. Backwash ileitis (BI). To recognise the backwash ileitis the full large bowel resected during proctocolectomy was analysed as a standard histological protocol. Results Pouchitis was observed in 66 patients, while backwash ileitis was presented in 30 patients, co-occurrence of pouchitis and backwash ileitis was described in 10 patients. Pouch dysplasia was found in 8 cases, pouch malignancy in 1 patient. Backwash ileitis positively correlated with the occurrence of each kind of dysplasia (p = 0.000001). However, the presence of pouchitis did not correlate with appearance of backwash ileitis in whole group (p = 0.2). Conclusions Occurrence of backwash ileitis do not correlate with the pouchitis frequency in operated patients, but in backwash ileitis patients severity of pouchitis (measured in PDAI score) is higher than in non-backwash ileitis group. In this group of patients (BI + pouchitis) the risk of dysplasia in pouch mucosa as higher and follow-up with endoscopies and biopsies is necessary.