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Dysplasia is more common in the distal than proximal colon in ulcerative colitis surveillance


  • Supported by grants from the Doris Duke Foundation (to R.G.), and National Institutes of Health (K-08-DK069393) (to T.U.). These organizations had no role in the study design, collection, analysis, or interpretation of data.



In patients with long-standing ulcerative colitis (UC), current dysplasia surveillance guidelines recommend four-quadrant biopsies every 10 cm throughout the colon. However, this may be inefficient if neoplastic lesions are localized in particular segments of the colorectum. The aim was to determine whether a difference exists in the anatomic distribution of dysplasia discovered in UC patients undergoing colonoscopic surveillance.


From an institutional database of over 700 patients with UC who underwent two or more surveillance colonoscopies between 1994–2006, we identified all patients with flat (endoscopically invisible) low-grade dysplasia (fLGD) or advanced neoplasia (colorectal cancer [CRC] or high-grade dysplasia [HGD]). Pathology reports were reviewed regarding the anatomic location of all dysplastic lesions. Fisher's exact test was used to compare the frequencies of neoplasia among the different colonic segments.


We identified 103 patients who progressed to any neoplasia (fLGD, HGD, or CRC). These patients underwent a total of 396 colonoscopies. The mean age at first surveillance colonoscopy was 48.6 years, with a mean UC disease duration of 18.2 years; 100% had extensive disease. Fifty-five patients developed advanced neoplasia. The rectosigmoid was found to have a significantly greater number of biopsies positive for advanced neoplasia and for any neoplasia compared to all other colonic segments (P < 0.0007); 71.2% of all advanced neoplasia was in the rectosigmoid.


The majority of dysplastic lesions identified in a surveillance program was detected in the rectosigmoid. Endoscopists should consider taking a greater percentage of biopsies in these segments as opposed to more proximal areas. (Inflamm Bowel Dis 2011;)