The diagnostic value of narrow band imaging in different oral and oropharyngeal subsites

The diagnostic value of narrow band imaging (NBI) in the "optical biopsy" of leukoplakias (LP) and erythroplakias (EP) in different oral cavity (OC) and oropharyngeal (OP) subsites is still to be defined. We evaluated 128 unbiopsied and untreated OC/OP LP and EP by conventional oral examination (COE), white light (WL) endoscopy, and NBI and categorized them as "suspicious" or "innocuous". All lesions were treated by excisional biopsy. True positives were those considered as "suspicious" and with histopathology ranging from mild dysplasia to invasive carcinoma. Epithelia were classified as follows: type 1, keratinized thick stratified (gingiva, hard palate, dorsal tongue); type 2a, non-keratinized thin stratified (floor of mouth, vestibule, ventral tongue, soft palate, palatine tonsils, base of tongue); type 2b, non-keratinized, very thick stratified (retromolar trigon, lateral tongue, labial and buccal mucosa). Histopathology revealed 32 % benign lesions, 13 % mild to moderate dysplasias, 15 % severe dysplasias/carcinoma in situ, 16 % microinvasive, and 23 % invasive carcinomas. The false positive rates were 32 % at COE, 27 % at WL, and 15 % at NBI. The false negative rates were 49, 22, and 11 %, respectively. Diagnositic performance was higher for NBI compared to COE (p < 0.001) and to WL (p = 0.004). Comparison of the diagnostic value of NBI among different OC/OP subsites did not show statistically significant difference. NBI as an "optical biopsy" tool significantly reduces the rates of false positives and false negatives in diagnosis of OC/OP cancer compared with COE and WL. No statistically significant difference was noted in its diagnostic value among different OC/OP subsites.