July 09, 2019
3 min read

Dentists detect growing number of oral cancers, precursor lesions

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Marco A. Magalhaes, DDS, MSc, PhD
Marco A. Magalhaes

The number of oral cancers and precursor lesions detected by dentists in Ontario increased sharply over a 10-year period, according to study results.

The study included 63,483 biopsies submitted by dentists between 2005 and 2015 to the Toronto Oral Pathology Service (TOPS) — one of Canada’s largest oral pathology services.

Investigators found those biopsy specimens resulted in the diagnoses of 828 cases of oral cancer and 2,679 cases of oral epithelial dysplasia. The number of oral cancer cases diagnosed nearly doubled during the study period, from 56 in 2005 to 103 in 2015, whereas the number of oral epithelial dysplasia cases increased almost fourfold, from 99 to 374.

“These numbers are important, because the number of diagnosed cases outpaced both the rise in population in Ontario and the increased number of dentists licensed in Ontario,” Marco A. Magalhaes, DDS, MSc, PhD, assistant professor at University of Toronto Faculty of Dentistry, and an oral pathologist for TOPS, said in a press release.

HemOnc Today spoke with Magalhaes about what prompted this research, how he and colleagues conducted the study, their findings, and what subsequent research may entail.

Question: What prompted this research ?

Answer : We never had the evidence to support what was happening to patients with biopsy performed by dentists. We did not know, for example, how many patients undergoing biopsy went on to have a diagnosis of cancer — a lot of evidence was missing in the literature. In practice, we were noticing an increased number of early cancers being discovered. We decided to conduct the research to show that patients seen for regular dental work were having these premalignant lesions diagnosed early.

Q: What makes this study unique?

A: A few features are quite unique. We not only reviewed 63,000 biopsies of premalignant and malignant oral lesions, but we also focused on the incidence of premalignant lesions, and there was no evidence of that in the literature.

Q: How did you conduct the study?

A: We have one of the largest services in Canada dedicated to biopsies submitted by dentists. By reviewing the data during an 11-year period, we were able to gain an idea of how well they are detecting all kinds of cancerous lesions. We then categorized the data based upon the diagnosis and performed statistical analyses to determine how the numbers changed over time.


Q: What did you find?

A: When comparing the number of oral cancers diagnosed in our service by dentists with the trend in oral cancers diagnosed in the general population, dentists were submitting far more biopsies of oral cancers and premalignant lesions. Specifically, we observed a nearly 84% increase in the number of cancers submitted by dentists compared with a 30% increase in oral cancers diagnosed by other health care providers. Thus, dentists are definitely playing a more significant role in the diagnosis of oral cancer.

Q: Did any of your findings surprise you?

A: Most of the findings support what we already were seeing in practice. The surprising finding was that dentists are submitting a significant number of premalignant lesions. We expected an increase, but not as big as we found. This confirms that dentists are doing a good job of diagnosing oral cancers clinically and performing biopsies, which is likely because of improved training, continuing education and increased awareness.

Q: D o you have plans for additional research on this topic ?

A: We are already conducting a follow-up study. We did not look at the specific demographics of the population, risk factors or characteristics of the lesions in the current study. We are now looking at this and are in the process of reviewing charts for more than 3,000 patients with oral premalignant lesions and oral cancer.

Q: Is there anything else that you would like to mention?

A: It is very important that the entire health team, including dentists, works together. Dentists have a key role in diagnosing early lesions, and if we are all aware of this, then maybe appropriate referrals are going to be conducted in the right time. – by Jennifer Southall


Abadeh A, et al. J Am Dent Assoc. 2019;doi:10.1016/j.adaj.2019.01.026.

For more information:

Marco A. Magalhaes , DDS, MSc, PhD, can be reached at University of Toronto, 124 Edward St., Room 495, Toronto, Ontario, Canada M5G1G6; email: Marco.Magalhaes@dentistry.utoronto.ca.

Disclosure: Magalhaes reports no relevant financial disclosures.