Real time light induced fluorescence endoscopy (LIFE) in the gastrointestinal (GI) tract

BACKGROUND: Light induced fluorescence point spectroscopy of the GI mucosa can differentiate normal mucosa from dysplasia/carcinoma and identify dysplastic lesions occult to routine white light endoscopy (RWLE). The purpose of this study was to determine if a real time LIFE imaging system of the GI tract (Xillix-LIFE, Vancouver) could differentiate normal mucosa from dysplasia/carcinoma. METHODS: 102 pts (59 male, mean age 65) consented to fluorescence imaging performed during routine colonoscopy(59) and gastroscopy (43). All procedures were documented with video and still images. In addition to RWLE, all mucosal abnormalities were examined with fluorescence using 437nm excitation. The images were reviewed separately by two endoscopist (GAD, RS) and the fluorescence was classified as a positive 'red' or a negative 'green' when compared with the normal 'green' surrounding mucosa. Tissue was obtained from the lesions and adjacent normal mucosa. In a blinded fashion, each sample was assigned a specific numerical diagnostic code by a single pathologist (1-4 denoting non-neoplastic changes, 6- 9 neoplastic, and 5 atypia of undetermined significance). The sensitivity/specificity of the Xillix-LIFE system was calculated by correlating the positive and negative fluorescence readings to the pathology codes. RESULTS: All lesions noted on RWLE were also seen using the Xillix-LIFE imaging system. Two high grade dysplastic lesions occult to RWLE, one in the colon of a pt with familial cancer syndrome and one in a Barrett's esophagus, were found only by fluorescence. Given the inconsistency of the current 'gain' standardization technique used for Barrett's esophagus, all cases of Barrett's esophagus without obvious carcinoma were excluded from the present analysis. The combined two-observer sensitivity/specificity for atypia or a higher grade lesion was 83%/84% and 87%/79% for the esophagus and colon, respectively. CONCLUSION:The real time Xillix-LIFE imaging system can screen the entire mucosal surface accurately differentiating normal from dysplasia/ carcinoma and target occult dysplastic lesions for directed biopsies. Further investigation is needed in the surveillance of Barrett's esophagus with fluorescence. Multi-center trials are needed to establish the clinical utility of fluorescence imaging in pts at high risk for GI cancer.