Colonoscopy and Sigmoidoscopy are Equally Effective for the Diagnosis of Colonic Acute Graft-versus-Host Disease in Patients with Diarrhea after Allogeneic Stem Cell Transplantation: A Prospective Controlled Trial

• We compared prospectively colonoscopy with sigmoidoscopy regarding their capabilities to provide a histopathologically proven diagnosis of colonic aGVHD after allogeneic stem cell transplantation.
• Sigmoidoscopy was as effective as colonoscopy in establishing a diagnosis of colonic aGVHD.
• The finding could have significant impact on clinical procedures, because it suggests the much less cumbersome sigmoidoscopy procedure is sufficient to establish an accurate diagnosis for these often critically ill patients.

Colonic acute graft-versus-host disease (aGVHD) affects approximately 10% of patients who have undergone allogeneic stem cell transplantation (allo-SCT). Diarrhea is a major clinical sign but also a common post-transplantation symptom in these patients. Comprehensive histopathologic examination of the colon is therefore regarded as crucial to establish a diagnosis, but the colonic segment that should be targeted for a diagnostic biopsy remains a topic of debate. The primary objective of this study was to compare prospectively colonoscopy with sigmoidoscopy regarding their capabilities to provide a histopathologically proven diagnosis of colonic aGVHD. Thirty-seven allo-SCT patients with diarrhea all underwent a colonoscopy. All biopsies collected from the descending colon were regarded as also attainable by sigmoidoscopy, whereas biopsies collected in regions further up the colon (from the transverse and ascending colon) were regarded as acquirable exclusively by colonoscopy. Biopsies attainable by colonoscopy and sigmoidoscopy were positive for GVHD in 25 (68%) and 24 (65%) patients, respectively (95% confidence interval for difference of proportions, −.185 to .245; P = .978; z = .0271 by the z-test). Sigmoidoscopy is as effective as colonoscopy in establishing a diagnosis of colonic aGVHD in patients who have diarrhea after allo-SCT.