Location of oral cancer varies in smokers and non-smokers
BRISBANE, Australia: Smoking and alcohol abuse are the most recognised factors in the causation of cancers of the oral cavity. However, a new ten-year study has shown that non-smokers too are at significant risk of oral squamous cell carcinoma. The study suggests that chronic dental or denture irritation in particular could be an important causative factor.
In order to determine whether oral cavity cancers occurred more commonly at sites of dental trauma, a comprehensive analysis of the medical records of 334 patients diagnosed with oropharyngeal cancer and 390 with oral cavity cancer was undertaken at Princess Alexandra Hospital in Brisbane between 2001 and 2011. Of the oropharyngeal cancer patients, almost 86 per cent were smokers or ex-smokers and about 14 per cent were non-smokers. Of the 390 patients with mouth cancer, 80 per cent were current or ex-smokers and about 20 per cent were non-smokers.
The researchers found that overall most mouth cancers occurred on the edge of the tongue. A significantly higher proportion of non-smokers (66 per cent, compared with 33 per cent in smokers), however, had mouth cancer in this location. In addition, they observed a higher incidence of mouth cancer in female non-smokers compared with male non-smokers.
As oral cavity cancers occurred predominantly at sites of potential dental and denture trauma, especially in non-smokers without other risk factors, the researchers concluded that the irritant effect of chronic dental trauma may induce the development of oral cavity cancers on the lateral tongue.
The findings suggest that dental trauma may be a more important and common carcinogen than is currently recognised, especially in cases involving non-smoking female patients, the researchers said.
The study, titled “Sites of origin of oral cavity cancer in nonsmokers vs smokers: Possible evidence of dental trauma carcinogenesis and its importance compared with human papillomavirus”, was published online on 6 November in the JAMA Otolaryngology—Head and Neck Surgery journal ahead of print.