______________________________________________ Oral Cancer and Complications of Cancer Therapies
HISTOPATHOLOGY OF CANCER
Classification
Cellular Activity
Malignancy
Status
Indication
Accelerated cell proliferation Cell structure is normal Accelerated cell proliferation Cell structure is changing Accelerated cell proliferation Cell structure is changing
Noncancerous
Potentially reversible
Cause must be investigated
Hyperplasia
Noncancerous
Potentially reversible, but may progress to cancer Noninvasive; does not extend beyond the epithelial membrane Likely to progress to invasive and metastasize Invasive; extends beyond epithelial membranes May have metastasized
Close monitoring is indicated
Dysplasia
Cancerous (very early)
Removal is indicated
Carcinoma in situ
Cell structure is completely aberrant
Cancerous
Immediate therapy is indicated
Invasive
Source: [16; 17; 18; 19]
Table 2
Diagnostic tools that precede traditional biopsy procedures have been developed. Toluidine blue, ViziLite, and computer- assisted brush biopsy analysis are such adjunctive techniques. These screening tools do not replace the traditional biopsy procedures but provide an initial assessment of a question- able lesion [8].
procedure. Further study is needed to determine what role, if any, this test should play in oral cancer screening [8]. The ultimate diagnosis of the lesion is still dependent on a biopsy procedure. TOLUIDINE BLUE Toluidine blue is a metachromatic dye that stains abnormal DNA, thereby identifying appropriate tissue for biopsy. Studies have proven its efficacy as a diagnostic adjunct in detecting the presence of potential malignant lesions, particularly in the early stages [8; 21; 22]. A Taiwanese study found a 79% increase in the detection of oral submucous fibrosis when using the dye compared to standard visual screening [23]. Sections suspected of being malignant lesions should be depa- raffinized and hydrated with distilled water. Then, the sections may be stained with toluidine blue solution for two to three minutes, after which the section should be thoroughly rinsed and dehydrated. Malignant cells will appear as violet or red purple against a blue background. THE ORAL CDX BRUSH BIOPSY SYSTEM The Oral CDx brush biopsy system is another means of attain- ing an initial assessment for suspect oral lesions [8]. The Oral CDx kit contains a sterile brush biopsy instrument, a precoded glass slide, a tissue fixative pouch, a requisition form, and a pre-addressed container into which the slide and requisition form are placed [24]. The brush biopsy instrument is a small, circular wire brush that is rotated several times over the lesion surface until the tissue is slightly pink or is just beginning to bleed. This slight degree of lesion penetration is usually done without topical or local anesthesia. The tissue sample on the brush biopsy instrument is then applied to the precoded glass slide, which is bathed in the tissue fixative. This sample undergoes analysis by the Oral CDx computer.
The American Dental Association does not recommend autofluorescence, tissue reflectance, or vital staining adjuncts for the evaluation of potentially malignant disorders among adult patients with clinically evident, seemingly innocuous,
or suspicious lesions. (https://jada.ada.org/article/S0002-8177(17)30701-8/ fulltext. Last accessed December 20, 2024.) Level of Evidence : Low or very low VIZILITE The principle upon which ViziLite works is based on the cell physiology of abnormal cells. These cells have a nuclear content and mitochondrial matrix that is denser than normal cells. The patient rinses with a special ViziLite solution for 60 seconds and expectorates the excess. This acetic acid rinse removes the adherent mucosal glycoprotein layer and increases the nuclear/cytoplasmic ratio via osmosis. A disposable handheld ViziLite is then passed over the oral tissues. Normal cells will absorb the light and appear dark. Abnormal cells, given the increased density of the nucleus and the mitochondrial matrix, will reflect the light and appear bright [20]. This reflection pattern from ViziLite provides for the detection beneath the epithelial surface. If a suspicious lesion is detected at or below the epithelial surface, the clinician should perform a biopsy or refer the patient to a specialist who is able to perform this
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