DETECTION OF ADENOCARCINOMA IN BARRETTS-ESOPHAGUS BY MEANS OF LASER-INDUCED FLUORESCENCE

Patients-Seven patients with Barrett's metaplastic epithelium and oeso phageal adenocarcinoma were investigated by means of laser induced flu orescence after low dose intravenous injection (0 . 35 mg/kg bw) of Ph otofrin (QLT, Vancouver, Canada). Laser induced fluorescence measureme nts were performed immediately after resection of the oesophagus. Meth ods-Laser induced fluorescence spectra were recorded from 15-30 locati ons in each surgical specimen from normal mucosa, Barrett's epithelium , and tumour tissue. Histological examination was performed on each lo cation to correlate the fluorescence spectral characteristics with his tological status of the epithelium (normal, metaplastic or malignant). Measurements were also performed during endoscopy in five patients to test the applicability of the method in a clinical setting. Fluoresce nce spectra were recorded and evaluated at characteristic wavelengths, and biopsy specimens were collected. Fluorescence ratios were calcula ted as the quotient of Photofrin fluorescence divided by autofluoresce nce. Results-The mean (SD) fluorescence ratio values were 0 . 10 (0 . 058) for normal oesophageal mucosa, 0 . 16 (0 . 073) for normal gastri c mucosa, 0 . 205 (0 . 17) for Barrett's epithelium with moderate dysp lasia, 0 . 79 (0 . 54) for severe dysplasia, and 0 . 78 (0 . 56) for a denocarcinoma. The highest fluorescence ratios were obtained for adeno carcinoma tissue, which could generally be distinguished from all nonm alignant tissue. Metaplastic Barrett's epithelium also yielded higher fluorescence ratios than did normal mucosa. Conclusions-The results su ggest that the technique can be used during endoscopy for real time ti ssue characterisation in the oesophagus, as an aid in detecting malign ant transformation not macroscopisally apparent at endoscopy.