Mouth Sores & Tongue Changes: Oral Cancer Signs

The mouth heals fast. Ordinary aphthous ulcers, a bitten cheek, a rubbing denture, a sharp filling, cold sores, thrush and burns from hot food all produce sores that hurt and then go, usually within one to two weeks. Pain is not the worrying feature. Persistence is.

Mouth changes become urgent when they affect breathing, swallowing or bleeding, rather than when they simply persist.

• Call 911 or go to an emergency department if… your tongue, the floor of your mouth or your throat is swelling and you have difficulty breathing, noisy breathing, drooling, or cannot swallow your saliva.
• Call 911 or go to an emergency department if… bleeding from your mouth will not stop after 10 minutes of firm pressure.
• Call your care team the same day if… pain is stopping you eating or drinking — little or dark urine, dry mouth, dizzy standing up.
• Call your care team the same day if… a sore has not healed in three weeks, or you have a red or white patch, a lump or thickening, numbness of the lip or tongue, loose teeth, a changed voice, or trouble moving your jaw or tongue.

A sore that has not healed in three weeks is the checkpoint to act on.

Three weeks is the threshold used across referral guidance. An ulcer or sore in the mouth that has not healed after three weeks, with no obvious cause, is grounds for assessment — not because it is likely to be cancer, but because three weeks is longer than ordinary healing takes and the test that settles it is quick.

Alongside a non-healing sore, these are the changes that prompt a look:

• A red patch, a white patch, or a mixed red and white patch on the gum, tongue, floor of the mouth or lining of the cheek.
• A lump or thickening anywhere in the mouth, or a persistent unexplained lump in the neck.
• Numbness of the lip or tongue, or mouth pain that does not settle.
• Loose teeth with no dental explanation, or dentures that suddenly do not fit.
• Difficulty chewing, swallowing, or moving the jaw or tongue.
• A persistent sore throat or the feeling of something caught, a changed or hoarse voice, or one-sided ear pain with a normal-looking ear.

Red patches deserve a specific mention. A velvety red patch, or a mixed red and white one, carries more concern than a plain white patch, and guidance recommends urgent dental assessment for these rather than waiting for the next routine check-up.

Cancer of the oropharynx — the tonsils and base of the tongue — behaves differently from cancer of the mouth itself. Around 70% of oropharyngeal cancers in the United States are caused by human papillomavirus, and they have become more common over recent decades, including in people who have never smoked. They often present not as a visible sore but as a painless lump in the neck, a persistent one-sided sore throat, or a sensation of something stuck.

Two practical points follow. First, there is no standard screening test for oropharyngeal cancer. A dental check examines the oral cavity, which is a different anatomical area from the oropharynx, so a clear dental exam does not rule out a throat cancer. Second, HPV vaccination is prevention, not treatment; it is routinely offered at ages 9 to 12, with catch-up for some older people.

Tobacco in every form and heavy alcohol remain major risk factors for cancers of the mouth itself, and the two together multiply each other's effect.

A dentist or doctor will look and feel: the whole lining of the mouth, under the tongue, the floor of the mouth, and the neck. If the concern is further back, an ear, nose and throat specialist may pass a thin flexible camera through the nose — uncomfortable for a moment and over in about a minute. A biopsy is what settles the question: sometimes a small sample under local anaesthetic, sometimes a needle sample of a neck lump taken under ultrasound guidance. Tissue is often tested for p16 as a marker of HPV involvement, because it changes both staging and treatment. CT or MRI follows if cancer is confirmed.

• A sore that is healing, however slowly: keep an eye on it.
• A sore that has not healed in three weeks: book an appointment. A dentist counts.
• A red, or red and white, patch: urgent assessment, not the next routine visit.
• A painless neck lump present more than three weeks, or persistent one-sided throat or ear pain: get seen.
• Swelling of the tongue or throat with difficulty breathing, noisy breathing or drooling: emergency care.

Photograph it with the date visible, and note when you first noticed it. If you have been reassured but the sore is still there past three weeks, it is entirely reasonable to go back and ask specifically whether it should now be biopsied or referred.

• NCI: HPV and Cancer
• NCI PDQ: Lip and Oral Cavity Cancer Treatment (patient version)
• NCI: Head and Neck Cancers Fact Sheet
• NICE NG12: Suspected cancer — recommendations by site (oral cancer)