A recent study showed strong correlations between rectosigmoidoscopy and colonoscopy in evaluations of disease activity and mucosal healing in patients with ulcerative colitis.
“Once the diagnosis is established, and when UC patients are included in clinical trials, endoscopy limited to the rectum and sigmoid is the standard to assess disease activity and endoscopic healing because it is believed that the most severe activity of UC is located in the distal colon,” Jean-Frédéric Colombel, MD, professor of medicine at the Dr. Henry D. Janowitz Division of Gastroenterology, Icahn School of Medicine at Mount Sinai, New York, and colleagues wrote. “However, little evidence supports this assertion, and some UC patients may harbor more severe endoscopic inflammation proximal to the sigmoid colon.”
During the phase 2 EUCALYPTUS trial of etrolizumab (Genentech) in patients with moderate to severely active UC who did not respond to standard therapy, 72% of endoscopies evaluated disease activity beyond the rectosigmoid, which allowed the research team to perform a post hoc analysis of endoscopy videos “to evaluate whether endoscopic assessment limited to the rectosigmoid adequately represents endoscopic activity of the more proximal colon, and how potential discrepancies might affect assessment of efficacy in the context of a randomized clinical trial.”
Of 331 videos of endoscopies recorded at baseline, week 6 and week 10, 239 videos included evaluations of colonic segments proximal to the rectosigmoid, and were analyzed for disease activity and endoscopic healing using Mayo Clinic endoscopic subscores (MCSe) and UC endoscopic index of severity (UCEIS) scores.
Rectosigmoidoscopy and colonoscopy findings agreed on the presence of active disease (MCSe ≥ 2) in 205 videos and the absence of active disease in 25 videos, resulting in a strong correlation (r = 0.84). When active disease was defined as an MCSe score of one of higher, the agreement increased (r = 0.96). Evaluations using the UCEIS showed more severe disease in the rectosigmoid vs. proximal colon (P < .0001), and also a strong correlation between rectosigmoidoscopy and colonoscopy (r = 0.92).
“Because of its strong ability to detect active disease, rectosigmoidoscopy should be sufficient in clinical practice for evaluating previously diagnosed patients with new symptoms. … However, in cases in which rectosigmoidoscopy has detected endoscopic healing in response to induction therapy, but symptoms persist, performance of a more extensive examination with colonoscopy is justified,” the researchers concluded. “In the clinical trial setting, this study suggests that if endoscopic healing is defined as an MCSe of 0, rectosigmoidoscopy is sufficient for efficacy analyses. However, if endoscopic healing is defined as an MCSe of 1 or less, these preliminary data suggest that colonoscopy is better than rectosigmoidoscopy for assessing the full extent of endoscopic healing for efficacy analyses of experimental therapies.” – by Adam Leitenberger
Disclosure: Colombel reports he has served as a consultant or advisory board member for AbbVie, ABScience, Amgen, Bristol-Myers Squibb, Celltrion, Danone, Enterome, Ferring Pharmaceuticals, Genentech, Giuliani SPA, Given Imaging, Janssen, Immune Pharmaceuticals, Medimmune, Merck, Millennium Pharmaceuticals, Neovacs, Nutrition Science Partners, Pfizer, Prometheus Laboratories, Protagonist Therapeutics, Receptos, Sanofi, Schering-Plough, Second Genome, Shire, Takeda, Teva Pharmaceuticals, Tigenix, UCB and Vertex. Please see the full study for a list of all other authors’ relevant financial disclosures.