Advancing Non-Invasive Diagnosis of Oral Epithelial Dysplasia: Comparative Insights from In Vivo Optical Coherence Tomography and Histopathology

Background: Oral epithelial dysplasia (OED) is considered one of the premalignant lesions for oral squamous cell carcinoma (OSCC), for which the five-year disease-free survival rate may vary widely. There has emerged in recent years, therefore, a significant niche for optical coherence tomography (OCT) to non-invasively examine tissue morphology. The present study was conducted to evaluate the diagnostic performance of OCT in distinguishing between mild, moderate, and severe dysplasias and carcinoma in situ (CIS) with histopathological correlations. Methods: This prospective, single-centre study included 120 patients with clinically suspicious oral lesions. All lesions underwent in vivo OCT imaging followed by surgical excision and a histopathological examination. The sensitivity, specificity, and AUC (area under the curve) were calculated as measures of diagnostic accuracy. Results: OCT demonstrated high diagnostic performance with sensitivity and specificity above 80% for all grades of dysplasia. The AUC values were highest for moderate dysplasia at 0.91 and mild dysplasia at 0.89. The Bland–Altman analysis revealed a high degree of agreement between OCT and histopathology regarding the tumour depth measurements. Interobserver agreement was substantial to almost perfect, with kappa values ranging from 0.74 to 0.85. OCT provided the key imaging features of epithelial thickening, basement membrane disruption, and architectural disorganization. These had good correlations with the grade of dysplasia: r = 0.75–0.82, p < 0.001. Conclusions: OCT is an established diagnostic technique that is non-invasive in nature for the diagnosis of OED; it can provide fine differentiation among grades of dysplasia and define the margins of a lesion.