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

  • Lips
  • Gums
  • Tongue
  • Inner lining of the cheeks
  • Roof of the mouth
  • Floor of the mouth

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 cancer 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 sore that doesn’t heal
  • A sore that bleeds
  • A growth, lump or thickening of the skin or lining of your mouth
  • Loose teeth
  • Poorly fitting dentures
  • Tongue pain
  • Jaw pain or stiffness
  • Difficult or painful chewing
  • Difficult or painful swallowing
  • Sore throat

Causes

Mouth cancer occurs when cells on your lips or in your mouth develop changes (mutations) in their DNA. These mutations allow cancer 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

Mouth cancer stages

Leukoplakia

Once mouth cancer is diagnosed, your doctor works to determine the extent, or stage, of your cancer. Mouth cancer staging tests may include:

  • Using a small camera to inspect your throat.During a procedure called endoscopy, your doctor may pass a small, flexible camera equipped with a light through your nose to examine your throat and voice box. Your doctor looks for signs that cancer has spread beyond your mouth. Endoscopy can be done in the doctor’s office and causes very little discomfort.
  • Imaging tests.A variety of imaging tests may help determine whether cancer has spread beyond your mouth. Imaging tests may include X-rays, computerized tomography (CT) scans, magnetic resonance imaging (MRI) and positron emission tomography (PET) scans, among others. Not everyone needs each test. Your doctor determines which tests are appropriate based on your condition.

Mouth cancer stages are indicated using Roman numerals I through IV. A lower stage, such as stage I, indicates a smaller cancer confined to one area. A higher stage, such as stage IV, indicates a larger tumor or that cancer has spread to other areas of the head or neck, or to other areas of the body. Your cancer’s stage helps your doctor determine your treatment options.