Overview

Mouth cancer refers to cancer that develops in any of the parts that make up the mouth (oral cavity). Mouth cancer can occur on the:

  • Lips
  • Gums
  • Tongue
  • Inner lining of the cheeks
  • Roof of the mouth
  • Floor of the mouth (under the tongue)

Cancer that occurs on the inside of the mouth is sometimes called oral cancer or oral cavity cancer.

Mouth cancer is one of several types of cancers grouped in a category called head and neck cancers. Mouth cancer and other head and neck cancers are often treated similarly.

Symptoms

Signs and symptoms of mouth cancer may include:

  • A lip or mouth sore that doesn't heal
  • A white or reddish patch on the inside of your mouth
  • Loose teeth
  • A growth or lump inside your mouth
  • Mouth pain
  • Ear pain
  • Difficult or painful swallowing

When to see a doctor

Make an appointment with your doctor or dentist if you have any persistent signs and symptoms that bother you and last more than two weeks. Your doctor will likely investigate other more common causes for your signs and symptoms first, such as an infection.

Causes

Mouth cancers form when cells on the lips or in the mouth develop changes (mutations) in their DNA. A cell's DNA contains the instructions that tell a cell what to do. The mutations changes tell the cells to continue growing and dividing when healthy cells would die. The accumulating abnormal mouth cancer cells can form a tumor. With time they may spread inside the mouth and on to other areas of the head and neck or other parts of the body.

Mouth cancers most commonly begin in the flat, thin cells (squamous cells) that line your lips and the inside of your mouth. Most oral cancers are squamous cell carcinomas.

It's not clear what causes the mutations in squamous cells that lead to mouth cancer. But doctors have identified factors that may increase the risk of mouth cancer.

Risk factors

Factors that can increase your risk of mouth cancer include:

  • Tobacco use of any kind, including cigarettes, cigars, pipes, chewing tobacco and snuff, among others
  • Heavy alcohol use
  • Excessive sun exposure to your lips
  • A sexually transmitted virus called human papillomavirus (HPV)
  • A weakened immune system

Prevention

There's no proven way to prevent mouth cancer. However, you can reduce your risk of mouth cancer if you:

  • Stop using tobacco or don't start. If you use tobacco, stop. If you don't use tobacco, don't start. Using tobacco, whether smoked or chewed, exposes the cells in your mouth to dangerous cancer-causing chemicals.
  • Drink alcohol only in moderation, if at all. Chronic excessive alcohol use can irritate the cells in your mouth, making them vulnerable to mouth cancer. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger.
  • Avoid excessive sun exposure to your lips. Protect the skin on your lips from the sun by staying in the shade when possible. Wear a broad-brimmed hat that effectively shades your entire face, including your mouth. Apply a sunscreen lip product as part of your routine sun protection regimen.
  • See your dentist regularly. As part of a routine dental exam, ask your dentist to inspect your entire mouth for abnormal areas that may indicate mouth cancer or precancerous changes.
By Mayo Clinic Staff