Facilitating clinicians in performing oral cancer screening examinations should be encouraged to identify occult, or further affirm the presence of potentially premalignant, dysplasias. Although specialists who see small precancerous lesions on a regular basis may object to the use of adjunctive screening technologies, it is my opinion based on my clinical experience, personal research and discussions with my colleagues, that they are valuable screening and decision-making tools for the majority of dental professionals when used appropriately in conjunction with a conventional examination.
Some of the facts about adjunctive screening tools may not have been clear in the July JADA article, "Adjunctive Techniques for Oral Cancer Examination and Lesion Diagnosis: A Systematic Review of the Literature," by Dr. Lauren Patton and colleagues (
JADA 2008;139[7]:896–905[Abstract/Free Full Text]
). For example, none of the tools mentioned is reported to be diagnostic; according to manufacturers’ statements, they are only screening adjuncts. Diagnosis can only be made via histological examination of a surgical biopsy specimen.
There should be a distinction made between visual screening systems and brush testing, which involves tissue sampling. The Vizilite (Zila Pharmaceuticals, Phoenix), the Microlux DL (AdDent, Danbury, Conn.) and the Orascoptic DK (Orascoptic, a Kerr Company, Middleton, Wis.) all use tissue reflectance with the assistance of an acetic acid rinse. All of these systems are indicated for amplifying the visualization of white or mixed lesions by reflectance of light off the superficial mucosal layers.
The VELscope (LED Dental, White Rock, British Columbia, Canada) uses no prerinse and is based on direct tissue fluorescence, which uses the metabolic properties of tissue growth to assist in identifying irregular tissue metabolism. According to the article, "tissue fluorescence in the oral cavity is variable and is affected by structural changes, metabolic activity, the presence of hemoglobin in the tissue, vessel dilatation ... ." However, the statement becomes obscure: "... and, possibly, inflammation."
If it is affected by the presence of hemoglobin and vessel dilation, then that is inflammation. The VELscope will identify localized inflammation, but diascopic blanching,1 a technique described on the VELscope training DVD, can be effective if done properly in differentiating inflammatory lesions from persistent lesions that may be premalignant.
To the best of my knowledge, the variability of tissue appearance has not been defined for acetowhite lesions detected with the Vizilite or with the VELscope to date. That expectation probably is as unrealistic as is quantifying the variation of healthy tissues under incandescent light inspection.
In my own experience, tolonium chloride is difficult to procure for routine clinical use, is technique-sensitive and has questionable repeatability for the same lesion in the same person. However, I know that a commercially prepared tolonium chloride solution is available only as part of the Vizilite Plus system. Interestingly, a recent publication gave an example photographically in which tolonium chloride failed to identify the full extent of dysplastic tissue compared with the extended margin identified by direct tissue fluorescence,2 which makes me question its predictability as a screening tool.
Physical examination in good lighting has been defended as the preliminary level of screening. Adjunctive visual screening technologies are available as a secondary level of screening for enhancing the clinician’s screening skills. Brush biopsy (Oral CDx; Oral CDx Laboratories, Suffern, N.Y.) may be a tertiary screening level, used for patient education and for supporting the use of surgical biopsies, as could liquid-based brush cytology, a viable alternative3 that was not discussed in this article. Only surgical biopsy will yield a definitive diagnosis.
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