In many cases the exact cause of cancer is not known. However, the primary cause of mouth and throat cancer is smoking. People who drink excess alcohol are also at risk and when mixed with tobacco use, their chance of developing cancer is much greater.
Another factor of cancers of the mouth, especially in the lips is prolonged exposure to sunlight or sun-beds, this is also the major cause of skin cancer. If you spend a lot of time outdoors, try to wear a wide brimmed hat and apply a high factor sun-cream to your face and lips.
Regular inhalation of coal dust, asbestos and diesel fumes may also increase the risk of developing throat cancer.