Endoscopic fluorescence detection of dysplasia in patients with Barrett's esophagus, ulcerative colitis, or adenomatous polyps after 5-aminolevulinicacid-induced protoporphyrin IX sensitization

Background: Surveillance of patients with Barrett's esophagus or ulcerative colitis for dysplasia is confined to biopsy specimens taken randomly durin g endoscopy because dysplasia remains undetectable by visual inspection. We attempted to visualize dysplastic tissue during endoscopy after sensitizat ion with 5-aminolevulinic acid (5-ALA) leading to accumulation and formatio n of protoporphyrin IX and induction of characteristic red fluorescence of the latter substance using blue light illumination. Methods: Six patients with histologically proven low- or high-grade dysplas ia (Barrett's esophagus 2, ulcerative colitis 1, Billroth-II stomach 1, rec tal polyps 2) were treated with oral administration of different concentrat ions of 5-ALA (10 to 20 mg/kg) or by local instillation of 3 gm 5-ALA in th e rectum. Endoscopic fluorescence detection was performed 1 to 6 hours afte r sensitization using a blue light source and compared with conventional wh ite light endoscopy Biopsies of fluorescent and nonfluorescent areas were c ompared with histologic findings. Results: Normal duodenal mucosa and squamous epithelium showed more intense 5-ALA-induced background red fluorescence compared with normal mucosa in t he stomach or Barrett's mucosa. Histologically, dysplasia was exclusively f ound in areas with red fluorescence. False-positive fluorescence was associ ated with microscopic inflammation of the mucosa or feces in the colon. 7Conclusions: 5-ALA-induced protoporphyrin IX fluorescence may be useful in the detection of dysplasia in the gastrointestinal tract by enhancement of endoscopic surveillance of patients at a high risk for dysplasia.