In Ireland in 2009, oral and pharyngeal cancer accounted for approximately 1.1% of all cancer registrations. Oral cancer incidence increases with age. In Ireland, the average annual incidence rates for the period 1994–2009 a for cancer within the oral cavity rises (excluding cancer of the lips, pharynx, sinus and salivary glands) from 0.24 per 100,000 for both males and females in the 25–29 years age group to 13.30 females and 20.54 males per 100,000 in the 85 years and older age group.
Though oral cancer remains more common in males there has been a shift in the gender distribution over the last decade. Of the new cases of oral and pharyngeal cancer registered in 1994, 24% were in women; this has risen to 32% in 2009. Studies also show increasing incidence in younger adults: UK cancer registries record 6% of all oral cancers in young people under the age of 45 years. The increasing incidence of oral cancer in younger adults (non-smokers) is associated with exposure to the human papilloma virus (HPV), whereas the increasing incidence of oral cancer in females results from an increased acceptability of tobacco and alcohol use among women.
Both smoking and alcohol are important independent risk factors for oral cancer and there is convincing evidence that their combined effect is synergistically greater than the sum of the risks associated with either. There is also evidence of a dose response with tobacco smoking: the more cigarettes consumed daily and the more years one has smoked, the greater the risk of oral cancer.
Other risk factors include a diet low in fresh fruit and vegetable, viral exposure (i.e., HPV), radiation exposure and, for cancers of the lip, excessive exposure to ultraviolet sunlight. A recent systematic review also found evidence that low socioeconomic status per se is significantly associated with increased oral cancer risk in both high- and low-income countries worldwide.
Although oral cancer can occur without any pre-cancer signs, a number of recognised precancerous lesions are also linked with smoking and alcohol consumption. Many of these have a whitish colour and may not be painful. While the number of these lesions (such as leukoplakia) which will become cancerous is extremely low, a considerably higher proportion of people with these lesions develop oral cancer than among the general population.
The key to the prevention of oral cancer is to not use tobacco (or to give up tobacco use if already a user), and to adopt a sensible approach to the consumption of alcohol. It is estimated that at least three-quarters of oral cancers could be prevented by eliminating tobacco smoking and reducing alcohol consumption.
A healthy diet with at least five servings of fresh fruit and vegetables may also reduce the risk of oral cancer. Oral cancer detected early has an extremely good prognosis (approx. 90% five-year survival rate).Despite this, the survival rate in Ireland is quite low (<50%) as 60% of cases present at an already advanced stage.
Possible warning signs of oral cancer should not be ignored and if they persist for more than three weeks should be brought to the attention of a medical or dental professional for immediate investigation. These signs include:
- A sore or ulcer in the mouth that does not heal
- White or red patches inside the mouth
- A lump in the mouth or neck
- Thickening or hardening of the cheek or tongue
- Difficulty chewing, swallowing or moving the tongue
- A persistant sore throat and hoarseness
- Persistent nosebleeds and a stuffy nose
- Unexplained loose teeth.