Evaluation of Two Non-Invasive Methods, High-Resolution Microendoscopy and Liquid-Based Cytology, for Detection of Oral Precancer

Cancers of the oral cavity (lip, oral tongue, gingivae, floor of mouth, hard palate, and other mouth tissues including buccal mucosa) are amongst the most common worldwide, with an estimated annual burden of over 300,000 incident cases. Most oral cancers (\>75%) are attributable to cigarette smoking, alcohol drinking, and chewing of areca nut/betel quid with or without tobacco, and very few are related to human papillomavirus infection. Oral cancer incidence geographically tracks with the prevalence of these risk factors and is notably high in the Indian subcontinent (due to tobacco chewing and smoking) and southeast Asia (due to betel quid chewing without tobacco and smoking). The current standard for screening for oral precancer/cancer is visual and tactile examination by an expert for the presence of clinical/visual lesions (leukoplakia, erythroplakia, and oral submucous fibrosis). Such visually identified lesions are further triaged based on clinical impression for a biopsy to determine histopathologic presence/grade of dysplasia. Several observations point to key limitations of oral cancer screening based on clinical impression-based biopsy of visually identified lesions, including the decision to biopsy a lesion, which lesion to biopsy, and where within the lesion to direct a biopsy. Thus, there is a need for tools for improved triage of visual precancers for biopsy and targeting areas for biopsy within a lesion for more effective risk stratification and better provision of care. Two non-invasive methods hold promise for triage of lesions for biopsy-oral liquid-based cytology and high-resolution microendoscopy (HRME). Oral cytology provides a method to non-invasively sample visible oral lesions and holds promise to enable triage of lesions for biopsy. HRME utilizes optical fiber-based imaging in combination with the fluorescent contrast agent proflavine to image sub-cellular features in vivo in lesions/epithelial tissues, functionally an in situ biopsy. The investigators propose to conduct a cross-sectional study to evaluate the clinical utility of these two non-invasive methods for detecting oral precancer and early oral cavity cancer- the performance of oral cytology and HRME as an adjunct for triage of visible lesions for biopsy and the performance of HRME as an adjunct to enable better within-lesion targeting of areas for biopsy. If successful, this study would facilitate the development of a non-invasive, 3-step algorithm for oral cancer screening: identification of lesions through visual inspection, triage for biopsy through cytology or HRME, and targeted within-lesion biopsy (if needed) through HRME.