The mouth (or oral cavity) is the area between the lips and top of the throat (or oropharynx). Learn more with this 3D animation.

What is oral cancer?

Cancer occurs when cells become abnormal, grow uncontrollably and have the potential to spread to other parts of the body. These cells build up to form a mass (or lump). 

Most oral cancers start in the cells that line the mouth (the mucosa; called squamous cell carcinomas, the same as the common types of skin cancer). Oral cancers can also start to grow in minor salivary glands, bone, blood vessels, nerves, and other structures. These cancers are rare and only make up less than 5% of oral cancers. 

What causes oral cancer?

Doctors often can’t explain why a person gets cancer. But we do know what makes some cancers more likely.

The two main causes of oral cancer are:
  • smoking (cigarettes, cigars or pipes) or using ‘smokeless’ tobacco (snuff and chewing tobacco) If a person smokes or has smoked in the past, they have a higher risk of getting oral cancer than someone who has never smoked. 

  • drinking alcohol. If a person drinks a lot of alcohol over many years, they have a higher risk of getting oral cancer, especially combined with smoking.

Three out of four people with oral cancer have been a smoker or consumed alcohol regularly for a number of years.

Other factors that may increase the risk of oral cancer are: 
being male – in Australia men are more likely than women to get oral cancer
age – most oral cancers (about 90%) are in people aged over 50 years
previous diagnosis of oral cancer
using mouthwash containing alcohol, over a number of years
using betel nut (betel quid) – oral cancers are more common in parts of Asia where betel quid is chewed
lichen planus – an inflammatory condition that causes white and red patches in the mouth (although less than 1 in 100 people with this condition develop oral cancer)
a poor diet low in fruit and vegetables
broken and sharp teeth rubbing on the tongue and cheek