Brush Biopsy: Brush Biopsy in Oral Risk Lesions

Brush biopsy (synonym: brush cytology) is a simple procedure for sampling cells from conspicuously altered areas of the oral mucosa and is used for early detection and control of oral risk lesions. Oral squamous cell carcinoma (squamous cell cancer of the oral cavity) is a common cancer, with an incidence (frequency of new cases) of approximately 10,000 new cases per year. The five-year survival rate for men is between 36 and 45 percent, and slightly higher for women, 50 to 63 percent. Cancers of the tongue, floor of the mouth, and pharynx have the least favorable prognosis. The median age of onset is 64 years for women and 60 years for men. The main risk factors for developing squamous cell carcinoma of the oral cavity are nicotine and alcohol, especially when both risk factors are present in combination. Other risk factors include inadequate oral hygiene, HVP viruses, chronic inflammation, and diets low in vitamins and high in meat. Often the disease is diagnosed late, with serious consequences for the patient. If the disease is diagnosed at an early stage and the tumor is removed at T1 stage, the five-year survival rate increases to about 90 percent. Oral precancerous lesions (precancerous lesions) such as leukoplakia (white efflorescences of the mucosa that cannot be wiped off; this is a keratinization disorder with cellular and epithelial atypia (cell deviations from the norm); leukoplakia belongs to the facultative precancerous lesions) and erythroplakia (reddish lesion belonging to the facultative precancerous lesions) must therefore be checked regularly by the dentist. The prevalence (disease frequency) of leukoplakia is given as 0.5 to 3.4 percent. Malignant degeneration occurs in 0.6 to 18 percent of cases. For other potential malignant oral mucosal lesions, see Indications below. A simple, less invasive method for evaluating oral mucosal lesions for malignancy potential is brush biopsy.

Indications (areas of application)

  • Potential malignant oral mucosal lesions:
    • Leukoplakia, erythroplakia, oral lichen planus (OLP; chronic inflammatory disease of the skin and mucous membranes; nodular lichen), mucosal changes due to “reverse smoking”, chronic candidiasis (collective name for infectious diseases caused by fungi of the genus Candida), cheilitis actinica (inflammation of the lips due to sun exposure), oral submucous fibrosis, chronic discoid lupus erythematosus (CDLE), Fanconi anemia, dyskeratosis congenita,
  • Ulcers (ulcers) without healing tendency, ie, also any non-healing wound.
  • Lesions with conspicuous surface structure
  • Control after previous negative brush biopsies in persistent lesions.
  • Control of lesions in patients with a history of head and neck cancer.

Contraindications

  • Highly conspicuous lesions with strong suspicion of malignancy.
  • Ulcer center
  • Lesions with inconspicuous, intact epithelial coverage – e.g., fibroma.

The procedure

Brush biospy represents a form of abrasion cytology. Cells are obtained from all mucosal layers down to the basal cell layer (lowest cell layer). For this purpose, the biopsy brush is rotated around its own axis several times with light pressure on the lesion to be examined. Anesthesia is not necessary for this procedure. The biopsy should be sufficiently deep and taken from the marginal area between the altered and healthy tissue. A slight punctate bleeding indicates that the cells have also been taken at depth. The cells obtained in this way are then spread out from the brush onto a microscope slide and fixed in place using fixative spray. After a drying period, the specimens are sent to a pathologist for evaluation. Cytologic evaluation is performed as described below:

  • Negative – for epithelial atypia.
  • Atypical – further clarification recommended
  • Positive – dysplasia or carcinoma.
  • Insufficient – insufficient cellular material, repeat recommended.

Often, the brush biopsy is evaluated both by computer and by the pathologist himself. If the result is negative, the lesions should continue to be monitored regularly by the dentist. If the result is positive, an excision biopsy follows.This means that a small piece of the oral mucosa lesion is removed. This is always performed at the transition from healthy to diseased oral mucosa. If the diagnosis is confirmed here as well, further diagnostics and therapy of the carcinoma must be started immediately: Often, an incidental finding, such as thrush colonization of the lesion, is also detected during the examination and can thus be subsequently treated. Other possible ancillary findings include:

  • Other neoplasms (neoplasms) – e.g. salivary gland tumors, metastases (daughter tumors).
  • Inflammations
  • Mycoses (fungal infections) – e.g. Candida albicans
  • Viral or bacterial infections

Benefit

Early detection of oral cavity carcinoma plays a major role in increasing survival. This demonstrates the importance of this simple method of monitoring high-risk oral lesions.