A Dental Hygienist’s Guide to Chairside Diagnostics for Oral Cancer

A Hygienist’s Guide to Chairside Diagnostics for Oral Cancer

Every hour of every day, someone dies from oral cancer. Oral cancer is often defined as squamous cell carcinoma of the oral cavity, including the lip, tongue and oropharynx. The National Cancer Institute’s Surveillance, Epidemiology, and Ends Results (SEER) program reports that 30% of oral cancers originate in the tongue, 17% in the lip, and 14% in the floor of the mouth.1 According to the Oral Cancer Foundation, at current rates, more than 34,000 cases in the United States and over 400,000 cases worldwide will be diagnosed this year.2 It is estimated that 8,000 Americans die from oral cancer each year and despite great strides in treatment, the 5-year survival rate has remained at less than 60% for the last 50 years.These patients are at increased risks for developing metastasis and subsequent malignancies .

Conventional Screening

Because early discovery and treatment remains the best way to ensure patient survival and quality of life, dental hygienists can make a profound difference in the lives of their patients. Historically, the oral examination, using conventional (incandescent) light, has been the mainstay of oral cancer screening protocols and dental hygienists are well trained in performing this comprehensive intra- and extra-oral examination. Some experts believe there is little scientific evidence supporting the conventional visual screening as a method to decrease the mortality associated with oral cancer.4-5

Once a suspicious lesion is identified, a systematic approach to assessment is recommended. This includes a thorough review of the medical/dental history, including discussion regarding risk factors of tobacco and alcohol use. Tobacco use is ranked as the highest risk factor for oral cancer in patients over 50 and dental hygienists should continue to question every patient, young and old, about tobacco use. The American Dental Hygienists’ Association launched a national campaign to assist dental hygienists in tobacco cessation. In-office resources and information can be found at Ask. Advise. Refer. and many states have individual programs, such as the California Dental Hygienists' Association. View the interview link below for program details and opportunities. as well as a thorough lesion inspection, differential diagnosis, diagnostic tests, definitive diagnosis and suggested management complete the systematic approach.It is generally agreed that the conventional oral examination is useful in the discovery of some pathologic oral lesions, but it does not accurately identify precancerous lesions.

New Technologies

Although the gold standard in oral cancer diagnosis is still the scalpel biopsy, new chairside technologies offer the clinician additional information to their visual examination of adult patients. These technologies are evidence-based, minimally invasive and designed to assist in identifying both malignant and premalignant lesions.

  • ViziLite Plus with TBlue630
    FDA cleared in 2005, this product is an enhancement of the original VIZILITE™ introduced in 2001. This system uses chemiluminescent technology to improve the visual identification of oral lesions and once identified, a blue phenothiazine dye is used to mark those lesions. Patients rinse with a 1% acetic acid solution for 30-60 seconds and a disposable chemiluminescent light source is activated. The treatment room’s lights must be dimmed and the oral tissues are examined by shining the blue-white light source in the oral cavity. Atypical lesions appear very white.

    The toluidine dye system is then applied on the lesion to further enhance the suspicious lesion. Although toluidine blue dye has validity in identifying high-grade dysplasia and early squamous cell carcinoma, its ability to identify premalignant lesions is not as well defined.6-7

    An advantage of the VIZILITE PLUS™ system is once the lesion is stained, it can be seen without the light device. The dentist must make the decision to monitor the lesion in question or refer the patient for a scalpel biopsy.

  • VELscope™
    The Visually Enhanced Lesion Scope received FDA clearance in 2006. It is a handheld screening device intended to enhance the visualization of oral mucosal abnormalities that may not be apparent to the naked eye. In addition, it is designed to help the surgeon identify clear margins during surgical excision of suspicious lesions.

    The VELscope emits a safe, high-energy cone of blue light that is absorbed by the tissues. The tissue then re-emits the absorbed energy in the form of a visible glow or fluorescence. The treatment room’s lights must be dimmed, and the clinician looks through the scope to assess the tissue color. Healthy tissue emits bright lime green fluorescence, while unhealthy tissue has a loss of fluorescence, resulting in a dark green to black color. Fluorescent visualization has been shown to identify all high-grade premalignant oral lesions8 , but identification of Class II (innocuous) lesions is limited.9

    A camera to document photographs or video images can be adapted to the scope.

    This system is noninvasive and does not require any pre-rinsing or stains. In 2008, the company launched the VELscope Vantage™ system, featuring a more powerful lamp technology that provides better fluorescence in ambient lighting and improved camera imaging.

  • ORAL CDx
    Introduced in 1999, the brush biopsy was designed to test visible clinical lesions that normally would not be subjected to a surgical biopsy because suspicion of carcinoma was low, based on the lesion’s clinical features. It is also extremely valuable as an adjunctive service following the use of either of the two initial screening technologies mentioned above.

A specially designed circular brush is used to obtain a sample of the cells within the suspected lesion. To capture enough epithelium cells, the clinician must firmly push and rotate the brush 5-15 times across the center and edges of the lesion until pinpoint bleeding is observed. The obtained cells are then transferred to a bar coded glass slide and a fixative is applied by the clinician. After drying the slide is inserted into a plastic container for mailing to the OralCDx Laboratories.

Computer analysis is used to identify abnormal cells and specially trained pathologists use both computer and standard microscopic evaluation to make the final diagnosis of the submitted cells. Early studies showed encouraging results related to the identification of precancerous lesions10 , but later studies have suggested a high level of false positives.11When an abnormal result is reported, a scalpel biopsy of the lesion must performed to determine a definitive diagnosis. Dental hygienists should check with their state board to determine if they may perform this procedure and at what level of supervision.

  • Saliva Testing
    Until recently, human saliva’s functional value has always outweighed its diagnostic capabilities. Emerging science uses saliva as a diagnostic tool to detect a variety of conditions and diseases, including oral cancer. Scientists have discovered discriminatory and diagnostic biomarkers in human saliva that are present in healthy people and people with disease. Seven oral cancer-related RNA molecules, called mRNA, have been recognized and show promise for early oral cancer discovery.12

A new cell-based sensor system shows promise in identifying oral cancer biomarkers from saliva in less than 10 minutes13and UCLA is currently testing their version of this lab-on-a-chip, called the Oral Fluid NanoSensor Test (OFNASET).14

Human papillomavirus (HPV) 16 is present in up to 60% of patients with head and neck squamous cell carcinoma and measurement of salivary HPV-16 shows great promise for early detection, recurrence of head and neck cancer and general surveillance. 15

Dental hygienists are the gatekeepers of oral health, responsible for and expected to detect abnormalities related to oral disease. We have witnessed remarkable growth in evidence-based research related to the early discovery and diagnosis of oral cancer. Integrating these technologies into clinical practice will be important as we continue to make life-saving decisions for our patients.

In addition, the American Dental Hygienists’ Association launched a national campaign to assist the dental hygienist in tobacco cessation. In-office resources and information can be found at Ask. Advise. Refer.and many states have individual programs, such as the California Dental Hygienists’ Association. 

References

  1. National Cancer Institute. Surveillance, Epidemiology, and End Results (SEER) Program, 1973-1998. (2001). Retrieved on June 1, 2008 from, http://seer.cancer.gov/csr/1973_1998/oralcav.pdf.
  2. Oral Cancer Foundation.(2008). Oral Cancer Facts. Retrieved on June 1, 2008 from, http://www.oralcancerfoundation.org/facts/.
  3. National Cancer Institute. (2007). SEER Cancer Statistics Review, 1975-2005. Retrieved on June1, 2008 from, http://seer.cancer.gov/csr/1975_2005/results_merged/sect_20_oral_cavity.pdf.
  4. Ramadas, K., Sankaranarayanan, R., Jaco, B.J., Thomas, G., Somanathan, T., Mahe, C., et al. (2003). Interim results from a cluster randomized controlled oral cancer screening trial in Kerala, India. Oral Oncology, 39(6), 580–588.
  5. Kujan, O., Glenny, A., Duxbury, J., Thakker, N., & Slaon, P. (2005). Evalution of screening strategies for improving oral cancer mortality: A cochrane systematic review. Journal of Dental Education, 69(2), 255-265.
  6. Williams, P. M., Poh, C.F., Hovan, A.J., & Rosin, M. P. (2008). Evaluation of a suspicious oral mucosal lesion. Journal of the Canadian Dental Association, 74(3), 275-280.
  7. Zhang, L., Williams, M, Poh, C.F., Laronde, D., Epstein, J.B., Durham, S.,et al. (2005). Toluidine blue staining identifies high-risk primary oral premalignant lesions with poor outcome. Cancer Research, 65(17), 8017-8021.
  8. Poh, C.F., Ng, S.P., Williams, P.M., Zhang, L., Laronde, D.M., Lane, P., et al. (2007). Direct fluorescence visualization of clinically occult high-risk oral premalignant disease using a simple hand-held device. Head Neck 29(1), 71–76.
  9. Lingen, M.W., Kalmar, J.R., Karrison, T., & Speight, P. M. (2008). Critical evaluation of diagnostic aids for the detection of oral cancer. Oral Oncology, 44(9), 10-22.
  10. Sciubba, J.J. (1999). Improving detection of precancerous and cancerous oral lesions. Computer assisted analysis of the oral brush biopsy. Journal of the American Dental Association, 133(3), 1445-1457.
  11. Rick, G.M., & Slater, L. (2003). Oral brush biopsy: the problem of false positives. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology & Endodontics, 96(3), 252.
  12. Li, Y., St John, M.A., Zhou, X., Kim, Y., Sinha, U., Jordan, R.C., Eisele, D., Abemayor, E., Elashoff, D., Park, N.H.,& Wong, D.T. (2004). Salivary transcriptome diagnostics for oral cancer detection. Clinical Cancer Research, 10(24), 8442-8450.
  13. Weigum, S.E., Floriano, P.N., Christodoulides, N., & McDevitt, J.T. (2007). Cell-based sensor for analysis of EGFR biomarker expression in oral cancer. Lab Chip,7(8),995-1003.
  14. Gau, V., & Wong, D. (2007). Oral fluid nanosensor test (OFNASET) with advanced electrochemical-based molecular analysis platform. Annals New York Academy of Sciences, 1098, 401-410
  15. Chuang, A.Y., Chuang, T. C., Chang, S., Zhou, S., Begum, S., Westra, W.H., Ha, P.K., Koch, W. M., & Caliano, J. (2008). Presence of HPV DNA in convalescent salivar rinses is an adverse prognostic marker in head and neck squamous cell carcinoma. In press, corrected proof.
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