Back to basics: Guidelines for oral cancer testing recommend the old approach
By Diane Peters
When screening patients for oral cancer, dentists can now reach for a whole range of commercial adjuncts for assistance.
These non- or minimally-invasive tests include cytology adjuncts, which allow dentists to quickly and painlessly collect cell samples from the mouth, often using a brush and obtaining results from a proprietary lab. Vital staining, meanwhile, involves applying a dye to oral tissues and noting colour changes to indicate precancer or cancer.
Faculty of Dentistry associate professor Marco Magalhaes has been working with the American Dental Association (ADA) and a panel of U.S.-based experts to develop a series of living evidence-informed guidelines for oral cancer screening. He says these adjuncts may look like they offer some benefits; however, a closer look at the evidence reveals they’re not helping dentists and their patients.
“In most cases, there’s no high-quality evidence to show they work, and in other cases, false-positive results lead to unnecessary biopsies and patient anxiety and stress. For the general dentist as a general tool, they’re not recommended.”
These tests—which come at a cost—add another step to the diagnostic process. If there is a worrisome result, “You still have to do a biopsy,” he says.
Nothing replaces the basics of oral cancer diagnosis: getting a patient history, examining the neck and mouth and, if there are suspected lesions, performing a biopsy and having it assessed in an accredited lab by a pathologist. “That’s the standard,” he says.
Magalhaes, who has been collaborating with researchers from places such as the University of Pennsylvania and University of Chicago, is helping the ADA assess several types of screening tools, one by one.
The first guideline, on cytology adjuncts, says, “Their use should be reserved for specific circumstances among adults with mucosal abnormalities when a biopsy is not possible or indicated.” A second report that came out in April on vital staining recommends, “against the use of vital staining as an adjunct.”
These tests are fairly accurate, with cytology adjuncts having very low rates of false negatives but up to 13,790 false positives per 100,000 tests. Any positive result must be checked with a full biopsy and false positives lead to unnecessary patient stress.
They may be useful in certain situations, such as for patients who cannot tolerate a traditional biopsy or who are living remotely without access to healthcare professionals and testing infrastructure.
To further assist in decision-making around oral cancer testing, the ADA has published an interactive infographic on its web site to remind dentists of best practices for oral cancer diagnosis. As well, the ADA’s site clearly breaks down some of the data behind the new guidelines.
Perhaps, in time, there will be a new test that can easily screen for oral cancer or help guide the clinical decision to perform a biopsy. It’s happening for other cancers—for instance, home swabs for human papillomavirus (HPV) are quickly becoming the standard across Canada, replacing the pap smear to screen for cervical cancer.
While the ADA will publish guidance on light-based adjuncts and salivary tests later in 2026, Magalhaes suspects the recommendations will not shift. “These tests can detect abnormal areas in the mouth, but there is no evidence they can improve our current gold standard. We’re not there yet.”
Top photo: Filip Rankovic Grobgaard (Upsplash)