Benign or Malignant?

Q: In the September 2006 issue, we discussed the use of adjunctive technologies— ViziLite Plus with TBlue630™*, the VELscope™**, and OralCDx^®*** Brush Biopsy—in finding oral cancer. Of the hundreds of precancerous lesions that are found by these technologies, how many turn into cancer?

A: Enough adequate follow-up data do not exist to cite exact figures. But hundreds of dental offices have confirmed that they have noticed precancerous lesions with adjunctive technologies, which have turned out to be malignancies. Certainly, this has occurred in our clinic, which is primarily a referral center from community dental offices. First off, we should remember that the purpose of these techniques is to encourage more dental offices to perform oral cancer examinations. This includes examination of the neck for lumps, the lips, and oropharynx (tonsillar fossa areas). Including this examination as part of the dental appointment has most certainly lead to the identification of lesions that otherwise would have been missed or ignored. When a deviation from normal is noted, adjunctive techniques help determine whether the lesion is benign, should be followed closely, or biopsied immediately. Remember, biopsy is the gold standard for establishing a definitive diagnosis. This begs the question of what if it is a false negative? All tests have the possibility for providing false negatives. This problem is overcome by the dental professional vigilantly tracking the lesion or deviation until it disappears. If a lesion persists and the diagnosis is unknown, it must be biopsied. Adjunctive techniques are to encourage biopsy to avoid delays in diagnosis. The most common precancerous lesion is leukoplakia. However, all leukoplakias are not the same. For example, those having a red component are at greater risk to represent epithelial dysplasia or carcinoma, and those that show dysplasia are at increased risk for transformation. My colleagues and I found in an 8-year follow-up study that the transformation of leukoplakia occurred in about 6% of the participants, but when microscopic dysplasia was found in the lesion, about 1/3 of those transformed.¹

Q: For the dental professional who determines that a lesion is precancerous, is it not possible to make a prediction on its severity?

A: Certain characteristics exist that are solid indicators of severity. As noted above, a red component to leukoplakia indicates a higher risk. If the patient says, “This lesion is irritating me or it bothers me all the time or particularly when I eat food,” this indicates a greater chance of dysplasia or an early malignancy. This symptom is usually due to inflammation. While certain clinical characteristics will indicate a probability of a dangerous lesion, the bottom line is that currently, there are no specific cell markers that can tell us with absolute certainty that a lesion will turn cancerous. Research is currently being conducted to determine if we can develop a very specific or accurate cell marker.

Q: Dental professionals often consider certain patient populations as more likely to develop oral cancers but can oral cancer occur in people with no known risk factors?

A: Yes, if you are beginning a study where you desire a high yield of people with oral cancer, then obviously individuals over 40 who smoke and drink are at highest risk. One of the trends—and this is throughout the world now—is the incidence of oral cancer on the lateral border of the tongue in patients under 40 without risk factors. Young patients with carcinomas of the tonsillar fossae are also included in this group. Why these cancers are increasingly appearing is unknown at this time. This might be associated with carcinogenic types of human papilloma viruses. Dental professionals should begin oral cancer examinations on adolescent patients to make sure they don’t have a malignant or a precancerous lesion. Individuals experiencing oral cancer at a younger age appear to be without traditional risk factors, which also implies a genetic factor(s).

REFERENCE

• Silverman S Jr, Gorsky M, Lozada F. Oral leukoplakia and malignant transformation: a follow-up study of 257 patients. Cancer. 1984;53:563.
• *Zila Pharmaceuticals Inc, Phoenix
• **LED Dental Inc, White Rock, British Columbia
• ***OralCDX® Laboratories, Suffern, NY

From Dimensions of Dental Hygiene. November 2006;4(11): 32.