Comparative Evaluation of Oral Brush Cytology and Toluidine Blue Staining in the Detection of Oral Epithelial Dysplasia: A Prospective Clinical Study

Introduction: Early detection of potentially malignant oral disorders and oral squamous cell carcinoma plays a critical role in reducing disease progression and improving patient survival. The present study aimed to comparatively evaluate the diagnostic efficacy of oral brush cytology and toluidine blue staining in detecting dysplastic and malignant oral lesions using histopathological examination as the gold standard. Materials and Methods: This prospective clinical study included 150 participants with clinically suspicious oral mucosal lesions. Oral brush cytology and toluidine blue staining were performed prior to incisional biopsy in all participants. Histopathological examination served as the reference standard for confirmation of dysplasia and malignancy. Diagnostic performance parameters, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic accuracy, area under the receiver operating characteristic curve (AUC), and Cohen’s kappa coefficient, were calculated and compared. Statistical analysis was performed, and p < 0.05 was considered statistically significant. Results: Histopathological examination revealed dysplastic or malignant changes in 102 lesions (68.0%). Oral brush cytology demonstrated sensitivity of 87.3%, specificity of 81.3%, PPV of 90.8%, NPV of 75.0%, and diagnostic accuracy of 85.3%. Toluidine blue staining showed sensitivity of 82.4%, specificity of 70.8%, PPV of 85.7%, NPV of 65.4%, and diagnostic accuracy of 78.7%. Oral brush cytology demonstrated significantly higher AUC (0.843 vs. 0.766; p = 0.038) and greater agreement with histopathology (κ = 0.672 vs. 0.527; p = 0.041) compared with toluidine blue staining. Combined positivity of both tests further improved agreement with histopathology (κ = 0.718). Conclusion: Within the limitations of the study, both oral brush cytology and toluidine blue staining demonstrated satisfactory diagnostic utility for identifying dysplastic and malignant oral lesions. However, oral brush cytology exhibited superior overall diagnostic performance and agreement with histopathology, suggesting its greater reliability as a non-invasive adjunctive screening tool for early detection of oral epithelial dysplasia and malignancy.