Dysplasia that develops in the setting of
inflammatory bowel disease precedes
colorectal cancer (CRC). The category of "indefinite for dysplasia (IND)" is used often in equivocal cases, but its clinical significance remains unclear. Flow cytometric analysis of
DNA content (
aneuploidy) has shown some promise in stratifying patients into low or high risk of CRC, but there are few reports that have specifically evaluated the outcome of IND. As such, we analyzed a series of 84 IND
inflammatory bowel disease patients seen at the University of Washington and Harborview Medical Centers from 2003 to 2013 to determine the outcome of IND. Hospital electronic medical records were further reviewed to correlate outcome with the type of lesion (flat versus polypoid),
primary sclerosing cholangitis, active
inflammation in the area of IND, and
DNA flow cytometric data. The data show that 13% of IND cases were found to have low-grade dysplasia, whereas only 2% of IND cases showed advanced
neoplasia (high-grade dysplasia or CRC) after a mean follow-up of 28 months. The risk of
neoplasia was not significantly associated with the type of lesion (P = .94 from log-rank test),
primary sclerosing cholangitis (P = .94), or active
inflammation (P = .41) in this cohort. However, the finding of
DNA aneuploidy at baseline IND was predictive of subsequent detection of
neoplasia (P = .037). IND patients with abnormal
DNA flow cytometric results may warrant more careful follow-up, but conversely, IND in the setting of normal
DNA content may require less frequent surveillance colonoscopy.