Tobacco Consumption Induced Changes in the Healthy Oral Mucosa and its Effect on Differential Diagnosis of Oral Lesions – A Clinical In Vivo Raman Spectroscopic Study

Abstract

Objective : To investigate tobacco consumption induced changes in the in vivo Raman spectra of oral mucosa of healthy volunteers and to study its effect on the differential diagnosis of oral lesions. Materials and Methods : The clinical in vivo study involved 28 healthy volunteers and 171 patients having malignant and potentially malignant lesions of the oral cavity. Twenty of the healthy volunteers had habits of either smoking and/or of chewing tobacco while the rest did not have any tobacco consumption habits. The in vivo Raman spectra were measured using a compact and portable near-infrared Raman spectroscopic system. A probability based multi-class diagnostic algorithm, developed for supervised classification, was employed to classify the whole set of measured tissue Raman spectra into various categories. Results : It was found that the Raman spectra of healthy volunteers with tobacco consumption habits could be separated from the spectra of those without any habit of tobacco consumption with an accuracy of over 95%. Further, it was found that exclusion of the spectral data of the oral cavity of the healthy volunteers from the reference normal database considerably improved the overall classification accuracy (92.3% as against 86%) of the algorithm in separing the oral lesions from the normal oral mucosa. Conclusion : The results of the clinical study demonstrate the potential of Raman spectroscopy in screening tobacco users who are at an increased risk of developing dysplasia or malignancy. Further, the results also show that for accurate discrimination of oral lesions based on their Raman spectra, the reference normal database should exclude spectral data of tobacco using healthy subjects.