Performance characteristics of fluorescence endoscope in detection of head and neck cancers.

Laser-induced fluorescence endoscopy (LIFE) is a noninvasive method for detecting early cancers in hollow organs. A laser-induced fluorescence endoscope that was designed for lung imaging was investigated for its effectiveness in comparison to white light endoscopy (WLE) in localizing head and neck cancers. A total of 196 images from 98 sites in 56 patients were graded into 5 levels from normal to definitely abnormal. A cutoff level to differentiate normal from abnormal images was chosen from a receiver operating characteristic curve. On this basis, LIFE (sensitivity, 92.86%; specificity, 78.57%) was observed to be more effective and reliable than WLE (sensitivity, 67.86%; specificity, 70%) in locating neoplastic foci and precancerous lesions. Nevertheless, WLE was helpful in presenting anatomic details. The reliability of LIFE varied from site to site. It excelled in examination of the oropharynx (sensitivity, 100%; specificity, 96.20%), but was less effective for lesions of the nasopharynx (sensitivity, 66.70%; specificity, 75.00%). In standardizing the test, interobserver variation was assessed, and good agreement in image interpretation was confirmed by statistical analysis. In conclusion, LIFE was found to be an effective and reliable tool for detecting head and neck cancers.