A study gathered more than 11 biopsies to analyze key pathologies that could develop into oral cancer.

A team from the Chair of Pathological Anatomy and Physiology of the Faculty of Dentistry of the Universidad Nacional de Rosario The research team is conducting an investigation to determine the prevalence of so-called "potentially malignant oral disorders," inflammatory conditions that can develop into cancer over time. To this end, they analyzed more than 11.500 biopsies performed between 1954 and 2023.

The study is part of a growing movement in various dental schools across the country, aimed at deepening the understanding of these lesions. “Unlike what were traditionally known as precancerous lesions, the World Health Organization updated the terminology and defined them as potentially malignant disorders, a designation that acknowledges that not all of them develop into cancer, but they do present that possibility,” explained researcher Gustavo Merletti.

“We decided to analyze all the biopsies in our archive, from 1954 to 2023, to determine the frequency and characteristics of these pathologies, their relationship with age, sex and epithelial alterations that may indicate an unfavorable evolution,” added Dr. Mariel Guenzelovich.

Three pathologies in focus

Among the more than eleven thousand samples, the team identified 728 biopsies corresponding to three pathologies of particular interest: leukoplakia, oral lichen planus, and actinic cheilitis. “These are inflammatory lesions of the oral cavity that can present, at a microscopic level, cellular alterations associated with the development of malignant tumors,” Guenzelovich explained.

Leukoplakia typically manifests as a white patch on the oral mucosa; oral lichen planus presents as whitish and/or reddish lesions with varied characteristics; and actinic cheilitis is an inflammation that causes pallor, ulceration, and loss of lip elasticity due to prolonged sun exposure. The latter was the most frequent and had the highest proportion of epithelial alterations, making it the pathology with the greatest potential for cancerization among those analyzed.

Regarding the location of the lesions, biopsy analysis showed that leukoplakia and oral lichen planus most frequently occur on the floor of the mouth and tongue, although they also commonly appear on the buccal mucosa, that is, the inner part of the cheeks. Actinic cheilitis, on the other hand, primarily affects the lower lip. The location on the floor of the mouth and tongue is epidemiologically relevant because these areas are highly vascularized and, in the event of malignant changes, could facilitate a more rapid spread of abnormal cells.

“We were surprised by the prevalence of actinic cheilitis. More attention has always been paid to the oral cavity itself than to the lips, but they are part of the same system. And all the recorded cases we found were on the lower lip, coinciding with what the global literature indicates,” Merletti pointed out, adding: “This is because solar radiation has a greater impact on the lower lip, while the upper lip is less exposed.”

The presence of actinic cheilitis demonstrates that the effects of the sun on the labial connective tissue are irreversible and can be exacerbated by other risk factors. “Smoking, alcohol consumption, and chronic trauma, such as prolonged use of ill-fitting prostheses, are elements that increase the likelihood of a lesion becoming malignant,” explained Guenzelovich.

The long-term effects of new consumption methods, such as e-cigarettes or the popularized vapes, are still unknown, as they contain multiple chemical compounds that could affect oral health. Over time, these substances could influence the development of cellular alterations, although this effect can only be epidemiologically assessed in the coming years.

These factors are compounded by the trend of tanning without adequate protection and the lack of public awareness campaigns about oral health in the mass media. “There’s a lot of talk about cavities or cosmetic dentistry, but almost nothing about other oral diseases. Oral health isn’t just about a pretty smile; it’s a matter of overall health,” Merletti emphasized.

The importance of early detection

Many of these lesions do not cause symptoms and can go unnoticed by the patient. Hence the importance of the dentist's role in early detection. "Sometimes they are an incidental finding during a routine checkup. That's why we insist that professionals look beyond the teeth and examine the entire oral cavity and lips," the researchers noted.

The Faculty of Dentistry at the National University of Rosario (UNR) promotes regular oral cancer screening campaigns, which consist of a quick and painless sample collection using a technique similar to a Pap smear. le A gentle scraping of the oral mucosa is performed, and the results are obtained in a week. "It's a simple and effective way to detect cellular alterations early," Merletti pointed out.

A starting point for future research

In addition to its diagnostic value, the review of this historical archive opens new avenues of research. The team plans to advance molecular and biochemical studies on the most recent samples, since many of the older ones, although still observable, do not retain the necessary conditions for applying new analytical technologies.

“This research provides a foundation for further investigation. It allows us to identify the most prevalent pathologies, align with international criteria, and guide future projects. It also reaffirms the role of our Department and the Pathology Laboratory Service as a reference center, providing services to other areas of the Faculty as well as to professionals in the region upon request,” Guenzelovich emphasized.

“Often, this type of work goes unnoticed because dentistry is quickly associated with clinical care, and since this work isn't done in front of the patient, it's not well-known. It involves many hours spent observing images under a microscope, something that even students initially struggle to grasp. But these studies allow us to determine if a lesion exists, whether certain cells or tissues are malignant or not, and thus be able to treat that pathology,” Merletti explained. 

With nearly seven decades of records, the Faculty of Dentistry at the National University of Rosario (UNR) has established itself as a leading institution in the study of oral diseases and their impact on public health. In addition to preserving a valuable scientific archive, the research aims to raise awareness about the importance of oral care beyond aesthetics and promote the prevention of oral cancer, a disease that is often overlooked but has a significant impact on the quality of life of those who suffer from it.

Journalist: Gonzalo J. García