Background and study aims: There is increasing interest in the use of autofluorescence endoscopic imaging systems for the detection of malignancies in the gastrointestinal tract. The purpose of this study was to investigate the autofluorescent color of cancer lesions, and the detection rate of cancer areas using an autofluorescence endoscopic imaging system. Concurrent histopathologic examination was used for comparison.
Patients and methods: This study involved a total of 50 stomach cancer patients (with a total of 61 lesions) undergoing surgery. Immediately after the resection, each lesion was observed using an autofluorescence endoscopic imaging system (LIFE-GI system, Light-Induced Fluorescence Endoscopy in the Gastrointestinal Tract). A total of 429 evaluation points in the specimens were selected according to tumor size. The images obtained in this way were assessed by comparison with histopathologic findings in terms of depth of invasion, thickness of the mucosa that had been invaded by cancer cells, and the histologic type of each cancer.
Results: Detection with the LIFE-GI system was possible in 58 of the 61 stomach cancer lesions (95.1%). When examined in detail with reference to sampling points, the detection rates of cancer areas according to depth of cancer cell invasion were 57.5 % for invasion to the mucosa, 74.3 % for invasion to the submucosa, and 88.1% for invasion to the muscularis propria or deeper. The detection rates increased as the depth of invasion increased, and they increased significantly as the mucosa invaded became thicker. Detection rates according to histologic type were 82% for differentiated cancer, and 61% for undifferentiated cancer. Most of the cancer areas appeared dark red. Light blue, brilliant red, and white areas were also observed.
Conclusions: Mucosal thickening as a result of cancer cell invasion had a large impact on the detection rate of the LIFE-GI system. As a result, this method may not be useful for the detection of undifferentiated cancer, which may invade in a more dispersed manner, without altering the mucosal thickness.