What is oral brush biopsy?

An oral brush biopsy is a technique to screen the oral cavity of individuals who have a high risk of developing mouth cancer.

This technique collects cells from the deeper layers of the mucus membrane of the mouth. The procedure involves minimal pain and bleeding. Early detection can significantly improve survival rates in patients. Such patients require less extensive surgical procedures than patients with late-stage lesions.

Only 50% of individuals who suffer from oral cancers survive till 5 years. This is mainly due to the diagnosis in the late stages. Many early-stage oral cancers and precancer lesions do not look suspicious and go undetected until they progress to an advanced stage. The brush biopsy enables dentists and doctors to evaluate suspicious lesions painlessly and accurately in the early stages.

Indications for a brush biopsy include: 

• Small, nonsuspicious, unexplained red or white spots inside the mouth and throat and on tongue.
• Smooth white masses or patches inside the mouth that need to be confirmed as noncancerous.

Contraindications for the brush biopsy are:

• Masses or areas that are highly suspicious and require immediate scalpel biopsy.
• Submucosal masses, pigmented lumps, and fibromas should be biopsied with a scalpel.

Brush biopsy technique:

The oral brush biopsy does not require a local anesthetic. It causes minimal bleeding and pain. The biopsy brush has two cutting surfaces, the flat end of the brush and the circular border. Either surface may be used to obtain the specimen. The flat surface of the brush is more suitable for lesions on the inner lining of lips whereas the circular end of the brush is utilized for taking a sample from the sides of the tongue and gums.

The brush biopsy instrument available is a presterilized package and is designed to capture cells from all three layers of the mass. The deeper layers of the oral epithelium are often the only layers that contain the precancerous cells. These are missed by traditional cytology methods. The brush biopsy overcomes this problem by sampling the tissue of the entire plaque or mass down to the basal cell layer.

The doctor or the dentist can perform the procedure. The cutting edge of the brush is placed against the lesion and rotated in a clockwise fashion while maintaining firm pressure. The brush is repeatedly rotated about 5-15 times. Red lesions and ulcerations generally require a little pressure and few rotations. White lesions require more pressure and more rotations to get an adequate sample. After a proper biopsy sample is taken, pinpoint bleeding is observed at the site.

The collected cells on the brush are transferred to the glass slide, which is provided in the kit, in the same rotating motion from one end of the slide to another. The glass slide is then flooded with a fixative that is supplied the kit, and then, the slide is set aside to dry. Usually, after 15-20 minutes, the fixative dries and the slide is ready to place into the slide holder, which is also supplied with the kit.

The analysis of the sample is done using a computer program called the OralCDx system. If no cellular abnormalities are detected, the report is “negative.” If cellular abnormalities are detected, the report is either “positive” or “atypical.”

All positive and atypical reports must be sent for a scalpel biopsy to confirm the diagnosis.