Mouth cancer may look like white patches, red patches, or tongue sores. It can affect areas like your lips and gums, too. Unlike noncancerous lesions, cancerous lesions do not tend to resolve after a few weeks.

An estimated 54,540 people will receive an oral cavity cancer or oropharyngeal cancer diagnosis in 2023, according to the American Cancer Society, and 11,580 of these cases will be fatal.

Oral cancer can affect any of the working parts of your mouth or oral cavity, which include the:

  • lips
  • tissue that lines lips and cheeks
  • front two-thirds of the tongue (the back third of the tongue, or base, is considered part of the oropharynx, or throat)
  • gums
  • floor of the mouth (underneath the tongue)
  • roof of the mouth

Although your teeth can’t get cancer, surrounding cancer can affect them.

When should you worry about a bump, sore, or swelling in your mouth? Here’s what to look for.

The flat cells that cover the surfaces of your mouth, tongue, and lips are called squamous cells. Most mouth cancers begin in these cells. A patch on your tongue, gums, tonsils, or lining of your mouth can signal trouble.

A white or red patch inside your mouth or on your lips may be a potential sign of squamous cell carcinoma.

How oral cancer looks and feels varies considerably. The skin may feel thicker or nodular, or there may be a persistent ulcer or erosion.

What is important to note is whether these changes persist. Noncancerous lesions tend to resolve in a few weeks.

Bright red patches in your mouth that look and feel velvety are called erythroplakia. They are often precancerous, meaning they can become cancerous. According to a 2022 systematic review, about 1 in 5 erythroplakia cases turn into cancer, a much lower rate than in earlier studies.

Still, it’s best not to ignore any vividly colored spots in your mouth. If you have erythroplakia, a dentist will take a biopsy of these cells.

A white or grayish patch inside your mouth or on your lips is called leukoplakia. The patches may be rough and hard and difficult to scrape off.

Causes of cell growth that produce these patches include:

  • an irritant, like a rough tooth, broken denture, or tobacco
  • chewing the inside of your cheek or lips
  • exposure to carcinogenic substances

These patches signal that the tissue is abnormal and can become malignant. However, in most cases, it will be benign.

Leukoplakia generally develops slowly, over a period of weeks or months.

A mixture of red and white patches in your mouth, called erythroleukoplakia, is an abnormal cell growth that’s more likely to become cancerous. You may see these patches before you feel them. In the early stages, mouth cancer may cause no pain.

See a dentist within 2 weeks if you notice a red and white patch.

You may find erythroplakia anywhere in your mouth, but they most often occur on the inner lining of your cheeks or the floor of your mouth.

Check your mouth carefully once a month for any irregularities. Use a magnifying mirror under a bright light to get a clear view.

Pull your tongue out gently with clean fingers and inspect underneath. Look at the sides of your tongue and the insides of your cheeks, and examine your lips inside and out.

Know how to distinguish a canker sore from something more serious. A canker sore inside your mouth often burns, stings, or tingles before it’s visible.

In the early stages, mouth cancer rarely causes any pain. Abnormal cell growth usually appears as flat patches.

A canker sore looks like an ulcer, usually with a depression in the center. The middle of the canker sore may appear white, gray, or yellow, and the edges may be red.

Canker sores are often painful, but they aren’t malignant. This means that they don’t become cancerous.

Canker sores usually heal within 2 weeks, so any sore, lump, or spot in your mouth that lasts longer needs a professional evaluation.

If you suspect you have oral cancer, see a dentist or doctor. The Society of Behavioral Medicine notes that any trained clinician can perform a visual exam of the mouth to look for signs of oral cancer.

They’ll also ask you about your symptoms. Other symptoms of mouth cancer may include:

  • mouth pain
  • difficulty swallowing
  • difficulty speaking
  • unexplained weight loss

If a healthcare professional detects anything suspicious, they may perform a biopsy to check for cancerous cells. This may involve cutting off a thin layer of the sore or collecting cells from the sore with a special brush.

A regular dental checkup twice a year is an important cancer screening tool. These visits allow a dentist to detect any signs of oral cancer in the earliest stages. A doctor may also check for signs of mouth cancer during a regular checkup.

Prompt treatment reduces the likelihood that precancerous cells will become malignant.

You can also reduce your risk of developing mouth cancer by avoiding tobacco products, including “dip,” “chew,” and cigarettes, all of which research links to mouth cancer.

Sores in your mouth are usually not cancerous. Still, it’s a good idea to see a doctor or dentist if you notice white, red, or mixed patches in your mouth or on your lips that don’t go away after a few weeks. They can perform tests to see if it’s more serious.