In patients with inflammatory bowel diseases (IBD) who underwent colonoscopic surveillance for colorectal neoplasia (CRN), indefinite dysplasia was independently associated with a significant increase in advanced CRN risk, according to a study published in Clinical Gastroenterology and Hepatology. If these findings are confirmed, the guidelines for CRN surveillance in patients with IBD should be revised.

Patients with colitis due to IBD are at increased risk of colorectal cancer (CRC), and gastroenterological societies universally recommend surveillance with early detection and management of CRN (defined as low-grade dysplasia [LGD], high-grade dysplasia [HGD], or CRC). Although a large body of evidence has established advanced CRN risk following an LGD diagnosis, the course and clinical significance of IND is less well-defined.

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This retrospective cohort analysis included patients with IBD undergoing CRN surveillance at a tertiary referral center between 2001 and 2017 (N=492). The primary outcome was advanced CRN incidence and the secondary outcomes were CRN or colectomy incidence; a secondary analysis compared the incidence of advanced CRN and colectomy among patients with IND vs LGD. Participants had colonic IBD for ≥8 years or concomitant primary sclerosing cholangitis, with no history of colectomy or advanced CRN (CRC or HGD). Consistent histopathologic grading of dysplasia was given, and Kaplan Meier methods were used to collect data on time to advanced CRN or colectomy. Patients were classified as IND, LGD, or no dysplasia (NoD). Independently associated factors were identified using multivariable Cox regression analysis.

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In 2149 patient-years (PY) of follow-up, 32 (6.5%) of participants developed ACRN. Eighty (16.3%) participants were categorized as LGD, 53 (10.8%) as IND, and 359 (73.0%) as NoD. Compared with NoD participants, those with IND had a significantly higher risk of ACRN (adjusted HR, 6.85; 95% CI, 1.78-26.4) and CRN (adjusted HR, 3.25; 95% CI, 1.50-7.05), but not colectomy (P =.78). Compared with IND, LGD was associated with a significantly higher risk of ACRN (P =.05). Following a diagnosis of NoD, the incidence rates of ACRN were 0.4% per PY, compared with 3.1% per PY for IND, and 8.4% per PY for LGD.

Study investigators concluded, “we have established that the diagnosis of IND in itself is an important, independent risk factor for ACRN. We look forward to prospective validation studies since the clinical significance of a diagnosis of IND was heretofore poorly defined. As such, no clinical guidelines have provided clear recommendations for the management of IND. In the future, IND should be considered in evidence-based risk-stratification models to guide optimal CRN surveillance and management among patients with IBD. Such models would allow for effective surveillance, and thereby limit the physical and psychological burden on patients, as well as societal healthcare costs.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Mahmoud R, Shah SC, Torres J, et al. Association between indefinite dysplasia and advanced neoplasia in patients with inflammatory bowel diseases undergoing surveillance [published online August 22, 2019]. Clin Gastroenterol Hepatol. doi: 10.1016/j.cgh.2019.08.032