Backwash ileitis and the risk of colon neoplasia in ulcerative colitis patients undergoing restorative proctocolectomy.

Background: The significance of backwash ileitis (BWI) relating to the risk of colon neoplasia in ulcerative colitis (UC) patients is controversial.

Aim: We investigated the association between BWI and the presence of colon neoplasia in the colectomy specimen.

Methods: From 4,198 UC patients in a prospectively maintained pouch database from 1983 to 2011, patients with extensive colitis and BWI (n = 178) in proctocolectomy were compared with 537 controls [extensive colitis (n = 385) and left-sided colitis (n = 152)] without ileal inflammation.

Results: Colon neoplasia (colon dysplasia and/or colon cancer) was seen in 32 (18 %) patients with BWI in contrast to 45 (11.7 %) with extensive colitis and 13 (8.6 %) with left-sided colitis alone (p = 0.03). Of those with BWI, colon cancer was seen in 10 patients (5.6 %), while low grade and high grade dysplasia were seen in 7 (3.9 %) and 15 (8.4 %) patients respectively. On multivariate analysis, the presence of BWI with extensive colitis [odds ratio (OR) = 3.53; 95 % confidence interval (CI) 1.01-12.30, p = 0.04], presence of primary sclerosing cholangitis (PSC) (OR = 5.79, 95 % CI 1.92-17.40, p = 0.002) and moderate to severe disease activity at UC diagnosis (OR 4.29, 95 % CI 2.06-9.01, p < 0.001) were associated with an increased risk for identifying any colon neoplasia. For colon cancer, the presence of PSC (OR = 11.30, 95 % CI 1.54-80.9, p = 0.01) was the only factor independently associated with an increased risk.

Conclusions: The presence of BWI with extensive colitis was associated with the risk of identifying colon neoplasia but not cancer alone in the proctocolectomy specimen.