We reported the usefulness of liquid-based cytology for oral mucosal lesions, based on the Bethesda system （Oral Bethesda system）. In November 2015, the Japanese Society of Clinical Cytology published new guidelines for oral cytology, and recommended a new report format for oral cytodiagnosis based on the Bethesda system. In this article, we report the clinical validity of this new format compared to the conventional class classification format in our hospital.
Materials and Methods: We obtained biopsy and excision specimens of one hundred and nine patients diagnosed with oral squamous cell carcinoma in our hospital, over a 3-year period between November 2013 and May 2017. We performed cytodiagnosis, and evaluated the site of lesion, sensitivity, and false-negative rate of diagnosis.
Results: Cytodiagnosis revealed SCC （Squamous cell carcinoma） in 60 cases （56%）, HSIL （High grade squamous intraepithelial lesion） in 27 cases （25%）, LSIL （Low grade squamous intraepithelial lesion） in 15 cases （14%） and NILM （Negative for intraepithelial lesion or malignancy） in 7 cases （6%）. The sensitivity and false-negative rate using the new reporting format were 94% and 6%, respectively, indicating that the new format is more useful than past criteria.
Conclusion: We strongly suggest that liquid-based oral cytology using the new report format based on the Bethesda system is a clinically useful screening diagnostic system, and has clinical value in oral cancer screening.