Brush Biopsy as a Screening Tool for Oral Cancer

Exfoliative cytology has not been a very diagnostic or useful screening method for oral cancer because hyperkeratosis and keratin itself interfere with cell obtainment and a greater proportion of diagnostic cells are below the surface (most at the basement membrane level) (Fig 1-1a). Similarly, the illumination test referred to as ViziLite used in uterine precancer lesions has not found a place in oral cancer screening and was denied approval by the American Dental Association. Today, the preferred screening tool is the brush biopsy technique, which enables a transepithelial capture of cells. With this method, a brush is rotated against the tissue until slight bleeding is observed, indicating that the brush has reached the basement membrane (Figs 1-1b and 1-1c). The cellular aggregate on the brush is transferred to a glass slide, fixed, and then analyzed by computer scans and pathologists trained specifically in oral brush biopsy interpretation. This method is preferred over an exfoliative biopsy because its simplicity and practicality allow its use by all practitioners, regardless of whether they have surgical training, and because it captures actual cells. Therefore, the technique can be applied to a wider segment of the population. However, it must be remembered that the brush biopsy technique is only a screening tool; a "positive" biopsy or atypical cell identification requires a follow-up incisional biopsy.

Fig 1-1a. Traditional exfoliative cytology is inadequate for sampling potentially dysplastic cells.

Fig 1-1b. The firm brush is able to capture deeper cells to the level of the basement membrane.

Fig 1-1c. Brush placed and rotated to capture epithelial cells.