Autofluorescence Spectroscopy in Premalignant Lesions and Oral Cancer

OBJECTIVES:Fluorescence spectroscopy, a non-invasive, real-time in-vivo diagnostic technique is being increasingly used in the field of oncology. It makes use of the presence of tissue alterations of dinucleotide, collagen or metabolic products of porphyrin, and has potential for use in early diagnosis of premalignant and malignant lesions.The present work was aimed to study native fluorescence characteristic of normal oral tissues, smoker's mucosa(S), premalignant lesions(PM) and oral cancer(OC). METHODS:Study group included: normal(n=25), smokers(n=25), patients with PM(n=20) and patients with OC(n=13). Bilateral emission and excitation scan was done in-vivo for all patients using Fluoromax2™. Four emissions scan at 280nm, 320nm, 340nm and 405nm and two excitation scan at 340nm or 390nm were performed. Normalization was done; ratio parameters, mean and standard deviation calculated. RESULTS:Excitation spectra: At 280nm(tryptophan) showed a primary peak emission at 338nm and a small peak at 468nm. The emission intensity at 338nm was: OC>PM>S>normal. OC showed 5-fold increase in the emission peak intensity. At 320nm(Collagen) normal and malignant tissue showed two prominent peaks and a valley. The fluorescence intensity was higher in premalignant lesions than smokers. At 340nm(NADH) the intensity of PM was between normal and S. At 405 nm(porphyrin) a broad peak at 630nm was seen in OC. The ratio parameter between NADH and porphyrin distinguished normal and OC with 100% sensitivity. CONCLUSIONS:Fluorescence spectroscopy was useful in distinguishing between normal and OC at excitation spectra that correspond to tryptophan, NADH and porphyrin.