Oral cancer develops in the lip, tongue, floor of the mouth, palate, gums, inner lining of the mouth, and throat.
It accounts for 2-4% of the cancers diagnosed annually in the United States. The risk factors for developing oral cancer include tobacco consumption in any form (chewing or smoking), heavy alcohol consumption, a spicy food diet, recurrent trauma to the mouth due to a broken tooth or ill-fitting dentures, human papillomavirus infection, etc.
Diagnosing cancers at an early stage is crucial to improving the survival rate and reducing the treatment expenses.
How do you screen for oral cancer?
Early detection of oral cancer by visual inspection of the mouth is proposed in the countries with high incidence. The ENT (ear, nose, and throat) surgeon or the dental surgeon may call the person for a routine check-up to examine the oral cavity for any abnormal white or red patches or mass. The various methods to distinguish cancerous lesions from the normal mucosa include the use of toluidine blue dye, brush biopsy, chemiluminescence, and tissue autofluorescence.
Types of oral cancers that involve the squamous cell present with visible changes in the oral mucosa. These may look like white patches (leukoplakia), red patches (erythroplakia), purple patches (lichen planus), submucous fibrosis, etc. Early identification and monitoring of these potentially cancerous lesions allow clinicians to detect and treat the early stages of oral cancers.
Apart from encouraging the self-examination of mouth for any abnormal patches and regular check-ups, the following methods may be used by the doctor to screen for oral cancers:
- The oral brush biopsy (OralCDx Brush Test system) is a method to collect a cell sample from the abnormal areas. A specially designed brush is used to collect cells, which are fixed and stained on a glass slide. These are then analyzed microscopically via a computer-based imaging system. Results are reported as "positive," "atypical," or “negative.” The abnormal reports (positive or atypical) need a biopsy to confirm cancer. The available evidence states that this test is highly sensitive and specific in detecting pre-cancerous changes in high-risk patients.
- Exfoliative cytology is a procedure to collect cells from the lip or oral cavity where a piece of cotton or small wooden stick is used to gently scrape cells from the abnormal areas of the lips, tongue, mouth, or throat. The cells are viewed under a microscope to find out if they are abnormal.
- Toluidine blue stain is a procedure in which the abnormal areas in the mouth are coated with a blue dye. The areas that stain darker are more likely to be cancerous or develop cancer.
- The ViziLite system by Zila Pharmaceuticals involves rinsing the mouth with a 1% acetic acid solution for 1 minute followed by the examination of the oral lining under a special light. The acetic acid slightly dehydrates the oral lining. The abnormal oral cells absorb and reflect the light in a different manner. The normal cells appear blue, whereas abnormal areas appear whiter with sharper margins.
- Tissue autofluorescence technique has been developed by LED Medical Diagnostics Incorporation in partnership with the British Columbia Cancer Agency and is marketed as the VELscope system. It is used to scan the abnormal cells inside the mouth. The normal oral mucosa emits a pale green autofluorescence when viewed through the handpiece instrument. The abnormal cells appear darker.
- Tissue fluorescence spectroscope system consists of a small optical fiber that produces various wavelengths of light. A graph records the reflected fluorescence from the tissue. Depending on whether the tissue is healthy or abnormal, the wavelength varies. The reports are generated by computer accordingly.