Nancy Index Scores of Chronic Inflammatory Bowel Disease Activity Associate With Development of Colorectal Neoplasia.

BACKGROUND & AIMS: The degree of histological and endoscopic disease activity has been associated with an increased risk of colorectal neoplasia (CRN) in patients with inflammatory bowel diseases (IBD), but no histological scoring systems have been validated for determining risk of CRN. We investigated the association between histological and endoscopic disease activity and risk of first CRN in patients with IBD who had negative findings from a surveillance colonoscopy.

METHODS: We performed a retrospective analysis of consecutive patients who underwent at least 2 colonoscopies at Saint Antoine Hospital in France from January 1, 1996 through March 1, 2015 and whose first procedure was a surveillance colonoscopy. Histological IBD activity was assessed by the Nancy histological index. Patients were followed for a mean 5.7±3.3 years. Logistic regression and generalized estimating equations were used to identify clinical, endoscopic and histologic factors associated with detection of neoplasia in the inflamed colon mucosa.

RESULTS: Among 398 patients who underwent 1277 colonoscopies, we identified 45 patients with CRN. Factors associated with CRN were primary sclerosing cholangitis (odds ratio [OR], 2.65; CI 95%, 1.06-6.61; p=0.04), age (OR per 1-year increase, 1.04; CI 95%, 1.01-1.07; p=0.003) and mean Nancy histological index during follow-up (per 1-unit increase, OR, 1.69; CI 95%, 1.29-2.21; p<0.001). After adjustment for established factors, chronic disease activity defined as detection of ulcerations at more than 50% of colonoscopies was not associated with an increased risk of CRN (OR, 1.24; CI 95%, 0.53-2.91; p=0.62).

CONCLUSIONS: In addition to established risk factors, we associated Nancy histological index scores with development of CRN. Histologic findings based on the Nancy histological index should therefore be included in determining risk of colonic neoplasia in patients with IBD.