Location of oral cancer varies in smokers and non-smokers 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.