Optical diagnostics in oral cancer: An update on Raman spectroscopic applications

Raman spectroscopy (RS) is a sensitive vibrational spectroscopic method that can detect even subtle biochemical changes during the onset of disease. Consequently, RS has been extensively investigated for disease diagnosis, including cancers. Oral cancers are known to suffer from dismal survival rates, which have not improved for several decades. As delayed diagnosis contributes to the low disease-free survival rate observed in oral cancers, RS has also been explored for the early diagnosis of oral cancers. This review summarizes the major developments in the field, including diagnosis, surgical margin assessment and prediction of treatment response, and in the overall management of oral cancers. The article comprises an overview of epidemiology, diagnosis, treatment, and recently introduced diagnostic adjuncts for oral cancers, the basic principle, instrumentation of RS, multivariate analysis that impart objectivity to the approach, and finally a discussion on the recent applications in oral cancers. PubMed and Google Scholar database have been used to compile information available online till December 2015.