Oral Health›Common problems

Mouth Cancer: Signs, Risk Factors and When to Get Checked

Most mouth ulcers, patches and lumps are not cancer, but any that do not clear up should be checked. Here are the signs, how long to wait before getting checked in the UK, Australia and the US, and how to lower your risk.

Updated September 2026·By the OHA editorial team·8 min read·How we write
Key takeaways
  • The most common signs are a mouth ulcer that does not heal, a red or white patch, or a lump in the mouth, on the lip or in the neck.
  • These signs usually have another cause, but get them checked. The NHS says to see a GP or dentist about an ulcer lasting more than 3 weeks; US and Australian dental bodies say 2 weeks.
  • Tobacco and alcohol are the main risk factors, especially together. Some types of HPV and sun on the lips also raise the risk.
  • Dentists check for signs of mouth cancer at routine check-ups, so keep going even if you wear dentures.
  • Not smoking, cutting down on alcohol and protecting your lips from the sun all lower the risk.

Mouth cancer (also called oral cancer) can affect any part of the mouth, including the gums, tongue, the inside of the cheeks and the lips. Cancer Research UK says most people with its symptoms do not have mouth cancer. The NHS says it is still important to get them checked, because if they are caused by cancer, finding it early may mean it is easier to treat.

What is mouth cancer?

healthdirect Australia describes mouth cancer as abnormal cells growing inside the mouth, which can form a lump known as a tumour. It explains that most mouth cancers are squamous cell carcinomas, which start in the thin, flat cells that line the mouth, nose and throat.

Cancer Research UK covers mouth cancer together with cancer of the oropharynx, the part of the throat just behind the mouth, which includes the tonsils and the back of the tongue.

The NHS says anyone can get mouth cancer, but the risk increases with age, and most people are diagnosed between the ages of 66 and 70. The US National Institute of Dental and Craniofacial Research (NIDCR) says it most often occurs in people over 40 and affects more than twice as many men as women.

What are the signs of mouth cancer?

Symptoms listed by the NHS, healthdirect, the Australian Dental Association and the NIDCR include:

  • a mouth ulcer (sore) that does not heal
  • a red or white patch inside the mouth
  • a lump or thickening inside the mouth, on the lip or in the neck
  • pain in the mouth that does not go away, or pain when chewing or swallowing
  • difficulty swallowing, speaking or moving the jaw or tongue
  • a hoarse (croaky) voice or change in your voice
  • a feeling that something is caught in your throat
  • bleeding or numbness in the mouth
  • dentures that stop fitting well
  • losing weight without trying

White patches are known as leukoplakia and red patches as erythroplakia. Cancer Research UK explains that these patches are not cancer, but if left untreated they may lead to cancer. It also notes that thrush, a fungal infection, can cause patches that usually rub off.

The Australian Dental Association says mouth cancer often causes no symptoms at first, and pain is more common when it is advanced, so painless changes are worth checking too. For the common, harmless kind of ulcer, see our guide to mouth ulcers.

How long should you wait before getting checked?

The timescale differs by country:

  • UK: the NHS says to see a GP (or a dentist) about a mouth ulcer that has lasted more than 3 weeks. The Oral Health Foundation says the same for any unusual change in the mouth, and NICE (the National Institute for Health and Care Excellence) uses the 3-week point in its referral guidance for health professionals.
  • Australia: the Australian Dental Association lists an ulcer that is present for longer than 2 weeks, or keeps coming back, as a sign to see your dentist. healthdirect gives no set time: it says to see your doctor or dentist about any symptoms or changes, or if you are unsure whether something is normal.
  • US: the NIDCR says to see a dentist or doctor if you have any of the symptoms for more than 2 weeks. The American Dental Association says to call your dentist right away if any of the warning signs last longer than two weeks.

The 2-week and 3-week figures are the point at which to stop waiting, not a reason to delay. The NHS attaches no waiting time to a lump or to a red or white patch.

When to see a dentist
  • A mouth ulcer has not healed within 2 to 3 weeks (see above), or ulcers keep coming back.
  • You notice a red or white patch, or a lump in your mouth, on your lip or in your neck.
  • You have mouth pain, difficulty swallowing or speaking, or a hoarse voice that is not going away.
  • You are unsure whether something in your mouth is normal.

What increases the risk?

Cancer Research UK says the cause of most mouth cancers is not known, and some people get them without any known risk factor. Listed risk factors include:

  • Tobacco. Smoking cigarettes, pipes or cigars, and chewing tobacco, betel nut or paan, all increase the risk (NHS, Cancer Research UK). The Australian Dental Association, healthdirect and the NIDCR also include vaping. Cancer Council Australia is more cautious, saying vaping may potentially increase the risk. See smoking, vaping and oral health.
  • Alcohol. The NHS lists drinking a lot of alcohol. Cancer Research UK, the Australian Dental Association and Cancer Council Australia say drinking and smoking together raise the risk further.
  • HPV (human papillomavirus). Cancer Research UK says this common virus spreads through close skin contact, usually during sex, and that the main type linked to these cancers is HPV 16. The link is much stronger for oropharyngeal (throat) cancers than for cancers inside the mouth, and only a very small number of people with HPV develop them.
  • Sun exposure on the lips. The NHS, the NIDCR and Cancer Council Australia link lip cancer to sun exposure; the NHS includes sunbeds.
  • Other factors listed by the NHS and Cancer Research UK include leukoplakia, a weakened immune system (for example from HIV or medicines taken after an organ transplant), having had certain cancers before, and a family history of head and neck cancer.

How is mouth cancer found?

Often at a dental check-up. The Australian Dental Association says dentists check for signs of cancer inside your mouth and around your face, head and neck during general check-ups, so you should still have check-ups if you wear full dentures. The NIDCR says the examination is painless and takes only a few minutes. See our guide to dental check-ups.

If you see a GP or dentist about a symptom, the NHS says they will usually ask questions and look and feel inside your mouth, and may feel your neck and jaw.

If they are concerned, you will be referred. In the UK this may be an urgent referral to a specialist, which the NHS says does not definitely mean you have cancer. In Australia, healthdirect says a dentist who suspects mouth cancer will refer you to your doctor. The main test is a biopsy, where a small sample of tissue is removed and checked for cancer cells. The NHS and healthdirect both say results usually come back within 2 weeks.

How is it treated?

The NHS says treatment depends on the size of the cancer, where it is, whether it has spread and your general health, and may include surgery, radiotherapy, chemotherapy, targeted medicines or immunotherapy, planned by a specialist team. The NHS says radiotherapy may be the only treatment needed if the cancer is found early.

Can you lower your risk?

Mouth cancer cannot always be prevented, but you can lower your risk:

  1. Do not smoke, and do not chew tobacco, betel nut or paan (NHS).
  2. Cut down on alcohol. The NHS advises not drinking more than 14 units a week.
  3. Protect your lips from the sun. The Australian Dental Association suggests a lip balm with a sun protection factor of at least 15.
  4. Eat a healthy diet with plenty of fruit and vegetables (NHS, NIDCR), and exercise regularly (NHS).
  5. Consider HPV vaccination. The NHS offers it to children aged 12 to 13 and lists mouth cancer among the cancers linked to HPV. The American Dental Association says the vaccine may also prevent oral cancers.
  6. Keep up regular dental check-ups. healthdirect advises seeing a dentist at least once a year, even if you have dentures.

Frequently asked questions

Is every mouth ulcer that lasts a while cancer?

No. The NHS says these symptoms are very common and can be caused by other conditions. A lasting ulcer is checked because, if it is cancer, finding it early may make it easier to treat.

Does mouthwash containing alcohol cause mouth cancer?

The Australian Dental Association says regular use of alcohol-containing mouthwashes is safe and has not been shown to increase the risk of oral cancer. See our guide to mouthwash.

Can young people get mouth cancer?

Yes, although it is more common with age. Cancer Research UK says people with HPV-positive throat cancer are generally younger and do not usually smoke, and the Oral Health Foundation says rates are increasing in younger people and in women.

Sources

  1. What is mouth cancer?, NHS, accessed September 2026
  2. Symptoms of mouth cancer, NHS, accessed September 2026
  3. Causes of mouth cancer, NHS, accessed September 2026
  4. Tests and next steps for mouth cancer, NHS, accessed September 2026
  5. Treatment for mouth cancer, NHS, accessed September 2026
  6. HPV vaccine, NHS, accessed September 2026
  7. Suspected cancer: recognition and referral (NG12), recommendations organised by site of cancer, NICE, accessed September 2026
  8. Symptoms of mouth and oropharyngeal cancer, Cancer Research UK, accessed September 2026
  9. Risks and causes of mouth and oropharyngeal cancer, Cancer Research UK, accessed September 2026
  10. Mouth cancer, Oral Health Foundation, accessed September 2026
  11. Mouth cancer, healthdirect Australia, accessed September 2026
  12. Oral cancer, Australian Dental Association, accessed September 2026
  13. Head and neck cancers symptoms and risk factors, Cancer Council Australia, accessed September 2026
  14. Oral cancer, NIH National Institute of Dental and Craniofacial Research, accessed September 2026
  15. Oral cancer, American Dental Association (MouthHealthy), accessed September 2026

This article is general information about oral health. It is not a diagnosis or a substitute for advice from a dentist or doctor who knows your situation. If you have pain, swelling, bleeding that does not settle, or a problem that is getting worse, see a dental professional. In an emergency, contact your local emergency service.

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