Ulcerative Colitis: 2 or 3 Biopsies Needed to Firmly Assess Disease Status

UC colonoscopy
ulcerative colitis, biopsy, microscopic image, colonoscopy, IBD
Investigators assessed the number of biopsies required to accurately determine microscopic disease activity in ulcerative colitis to achieve the optimal biopsy protocol.

Reliable assessment of ulcerative colitis (UC) disease status in a single colonic segment required the collection of 2 or 3 biopsies. These results, from a retrospective cohort study, were published in Alimentary Pharmacology and Therapeutics.

Investigators collected 287 biopsies at the University of California, San Diego, inflammatory bowel disease biobank between 2014 and 2017. The biobank included DNA, blood, stool, and tissue samples with endoscopic video footage. Researchers analyzed rectosigmoid and colonic proximal to the splenic flexure biopsies from 46 patients, each with a minimum of 4 collected samples.

The median age of patients was 45.8 (range, 30.3-61.9) years; 52% were women; the mean Mayo Clinic Endoscopic Subscore was 1.23±1.13; 64% were on biologic and 36% on immunosuppressant therapies; and investigators collected a median of 5 (interquartile range [IQR], 4-7.75) biopsies per patient.

Compared with 4 biopsies, 3 biopsies reached an acceptable agreement (acceptance interval, −8.25 to 8.25), with a tolerance interval of −4.86 to 3.46, as did 2 biopsies (tolerance interval, −7.66 to 4.79), as measured by the Robarts Histopathology Index (RHI). Just 1 biopsy did not achieve an acceptable agreement (tolerance interval, −13.99 to 7.78).

Using the Geboes score, compared with 4 biopsies, 3 biopsies achieved an acceptable agreement (−1.25 to 1.25; tolerance interval, −1.2 to 0.9) but not 2 biopsies (tolerance interval, −1.75 to 1.1) or 1 (tolerance interval, −3.11 to 1.63) biopsy.

Compared with biopsies from the rectosigmoid colon, biopsies obtained from the ascending colon (RHI tolerance interval, −28.9 to 25) or the transverse colon (RHI tolerance interval, −29.1 to 23.1) did not reach acceptable agreement (RHI acceptance interval, −7.5 to 7.5).

The investigators observed a correlation between RHI scores and Mayo Clinic Endoscopic Subscores (r =0.81; 95% CI, 0.71-0.92; P <.0001), UC Endoscopic Index of Severity (r =0.78; 95% CI, 0.65-0.89; P <.0001), stool frequency (r =0.45; 95% CI, 0.3-0.76; P =.002), and rectal bleeding (r =0.4; 95% CI, 0.15-0.75; P =.006).

The major limitations of this study were the low sample size and the fact that investigators were unable to standardize the endoscopic biopsy sampling methods.

The study authors concluded that these data indicated at least 2, but optimally 3, biopsies were needed to dependably assess disease activity among patients with UC.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of authors’ disclosures.

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Battat R, Casteele NV, Pai RK, et al. Evaluating the optimum number of biopsies to assess histological inflammation in ulcerative colitis: a retrospective cohort study. Published online September 27, 2020. Aliment Pharmacol Ther. doi: 10.1111/apt.16083