Low frequency of colonic dysplasias in patients with longstanding IBD-colitis

T Ochsenkuhn, MD, a C Tillack, MD, a H Stepp MD, b R Baumgartner, MD, b B Goeke, MD,a M Sackmann, MD, a

aDepartment of Medicine II, Klinikum Grosshadern, University of Munich, Germany bLaser Research Institute, Klinikum Grosshadern, University of Munich, Germany

Background and aim: Patients with long-standing inflammatory bowel disease (IBD) have an increased risk to develop colonic dysplasias. By conventional colonoscopy dysplasias are likely to be missed. In pilot studies endoscopic fluorescence imaging evolved as a promising new technique to differentiate between normal colonic mucosa and dysplasia. We, therefore, used this technique to prospectively evaluate the occurrence of dysplasias in patients with longstanding IBD. Methods:. 25 consecutive patients (n=17 with ulcerative colitis, n=4 with Crohn´s colitis, n=4 with indeterminate colitis, mean age 44 years, range 31-73) with longstanding IBD-colitis and being in low activity or remission were screened for colonic dysplasias. To induce tumor-selective intracellular synthesis of red-fluorescent protoporphyrin IX, its precursor, 5-aminolevulinic acid, was given orally at a dose of 1g 3-4 hours before examination. Patients were examined by both conventional white light colonoscopy and by fluorescence imaging using a blue light source (400-410 nm) and a sensitive camera to detect fluorescence (D-Light/Tricam SL, Storz, Germany). According to WHO recommendations routine biopsies were taken every 10 cm from normal appearing mucosa and from macroscopically suspicious areas. In addition, fluorescence-positive areas had to be biopsied. All examinations were videotaped. Results: The median duration of the IBD was 14 years (range 4 Â 30 years). In all patients complete colonoscopy was performed. Fluorescence was negative in all but one patient. However, in this one patient, histology revealed no dysplastic tissue, thus the rate of false-positive results was only 4%. In none of the biopsies dysplasias were detected histopathologically, thus no false negative results were found. Except for one patient with a skin rash after sun exposure, no adverse effects were observed. Conclusions: Thorough endoscopic examination with a dense net of biopsies, in addition to fluorescence analysis, revealed no dysplasias in the colon of 25 patients with longstanding IBD-colitis. These data show that the rate of colonic dysplasias in patients with long-standing IBD-colitis may be lower than previously reported.

KEY WORDS: Colitis, Dysplasia, Photodynamic, Aminolevulinic Acid, Colonoscopy.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Risk Assessment, Part 1.