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Health condition · Clinically reviewed

Mouth cancer, the warning signs and why 3 weeks matters.

A mouth ulcer that will not heal is the single most important sign not to ignore. Early recognition and a fast referral pathway make the biggest difference to outcomes.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE NG12, head and neck MDT standards and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance including 2-week-wait referral criteria and MDT-led management.

Key facts

Mouth cancer at a glance.

The essentials, in plain English - what it is, who is at risk, and how it's diagnosed and treated in the UK today.

  • What it is

    A malignant growth of the lip, tongue, floor of mouth, gum or palate - almost always squamous cell carcinoma.

  • Main risk factors

    Tobacco (smoked and smokeless), alcohol, HPV infection, betel quid chewing and poor oral hygiene - tobacco and alcohol act synergistically.

  • Key red flag

    A mouth ulcer that has not healed within 3 weeks is the single most important warning sign.

  • Referral pathway

    Suspicious features trigger an urgent 2-week-wait referral to oral and maxillofacial or ENT under NICE NG12.

  • Diagnosis

    Confirmed by biopsy, with CT, MRI or PET-CT used to stage the disease before treatment planning.

  • Treatment

    Surgery, radiotherapy and chemotherapy, alone or combined, decided by a head and neck cancer MDT.

Why this guide matters

Early recognition changes outcomes.

Mouth cancer caught early is far more treatable. The three points below shape everything else on this page.

  • The 3-week rule matters

    Any mouth ulcer, red or white patch, or lump that persists beyond 3 weeks needs assessment - do not wait for it to worsen.

  • Tobacco and alcohol compound risk

    Used together, tobacco and alcohol raise risk far more than either alone - stopping both is protective at every stage.

  • The MDT drives every decision

    Treatment for confirmed mouth cancer is planned by a head and neck multidisciplinary team, not by a single specialist alone.

How the diagnosis is made

From a persistent ulcer to a clear plan.

The steps a UK GP, dentist or specialist will normally follow, in order - so you know what to expect and why.

  1. 01

    Recognising

    Recognising a persistent lesion

    A mouth ulcer, red or white patch, or lump that has not resolved within 3 weeks prompts assessment by a GP or dentist.

  2. 02

    Recognising

    Oral and neck examination

    Careful inspection of the whole mouth, tongue and floor of mouth, plus palpation of the neck for enlarged lymph nodes.

  3. 03

    Recognising

    Urgent 2-week-wait referral

    Suspicious ulceration, unexplained lumps or red/white patches meet NICE NG12 criteria for urgent oral and maxillofacial or ENT referral.

  4. 04

    Confirming

    Specialist examination

    A head and neck specialist assesses the lesion in detail, often with nasendoscopy to check the wider airway and throat.

  5. 05

    Confirming

    Biopsy for histology

    A tissue sample confirms squamous cell carcinoma and gives the grade needed to plan treatment.

  6. 06

    Planning

    Staging imaging

    CT, MRI or PET-CT map the size of the tumour and check for spread to lymph nodes or distant sites.

  7. 07

    Planning

    Head and neck MDT discussion

    A multidisciplinary team of surgeons, oncologists and allied specialists agree the treatment plan together.

Typical timeline: urgent referral to specialist assessment within 2 weeks.

Symptoms

What mouth cancer actually looks like.

The features that should prompt assessment, and those that mean it's time to seek urgent help.

  • Non-healing mouth ulcer

    A single ulcer persisting beyond 3 weeks is the classic warning sign and should never be dismissed as a minor sore.

  • Red or white patches

    Erythroplakia (red) or leukoplakia (white) patches on the tongue, gum or cheek can represent pre-cancerous or cancerous change.

  • Lump in the mouth or neck

    An unexplained, firm lump inside the mouth or a swollen lymph node in the neck warrants urgent assessment.

  • Pain or difficulty swallowing

    Persistent discomfort or difficulty swallowing (odynophagia or dysphagia) that does not settle needs review.

  • Numbness

    Unexplained numbness of the lip, tongue or chin can indicate nerve involvement from a deeper tumour.

  • Loose teeth without dental cause

    Teeth becoming loose or a socket failing to heal after extraction, with no obvious dental explanation, is a warning sign.

  • Persistent hoarseness

    Hoarseness lasting more than 3 weeks, especially alongside other symptoms, should prompt ENT assessment.

  • Red flag - rapid growth or bleeding

    A lesion that grows quickly, bleeds easily or is fixed to underlying tissue needs same-day medical attention.

Treatment

How mouth cancer is treated in the UK.

Surgery, radiotherapy and chemotherapy, alone or combined, with supportive care built around every patient.

  • Surgical resection

    Removal of the tumour with a margin of healthy tissue - the mainstay for accessible, earlier-stage disease.

  • Reconstruction

    Flap or graft reconstruction restores form and function after larger resections, often in the same operation.

  • Radiotherapy

    Used alone for some early cancers or after surgery to reduce the risk of recurrence in higher-risk disease.

  • Chemotherapy

    Usually combined with radiotherapy (chemoradiotherapy) for locally advanced disease, or used palliatively in metastatic cases.

  • Combination therapy

    Surgery plus radiotherapy, with or without chemotherapy, is common for larger or node-positive tumours, agreed by the MDT.

  • Speech and language therapy

    Supports swallowing and speech before and after treatment, particularly following surgery to the tongue or floor of mouth.

  • Dietitian support

    Helps maintain nutrition through treatment, including feeding tube planning when swallowing is significantly affected.

  • Smoking and alcohol cessation

    Stopping tobacco and reducing alcohol improves treatment outcomes and cuts the risk of a second primary cancer.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or dentist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Suspected cancer: recognition and referral (NG12).

  • National Cancer Registration and Analysis Service. Head and neck cancer statistics.

  • Royal College of Surgeons. Head and neck cancer multidisciplinary management guidance.

  • Cancer Research UK. Mouth and oropharyngeal cancer risk factors and outcomes.

Red flags

When symptoms need urgent attention.

These are the features that should never be watched and waited on - a specialist opinion is needed promptly.

  • Ulcer unhealed beyond 3 weeks

    The single most important red flag in mouth cancer - any ulcer persisting this long needs urgent assessment.

  • Unexplained lump in the neck

    A firm, painless, enlarging neck lump can indicate lymph node spread and needs same-week specialist review.

  • Fixed or indurated lesion

    A lesion that feels hard or fixed to deeper tissue rather than soft and mobile is more concerning for malignancy.

  • Rapid growth or bleeding

    Fast-growing lesions or those that bleed spontaneously need same-day medical attention.

  • Nerve symptoms

    New numbness or weakness affecting the tongue, lip or face can signal nerve involvement from a deeper tumour.

  • Unexplained weight loss

    Weight loss alongside a mouth lesion or throat symptoms raises concern for more advanced disease.

  • Persistent hoarseness with other signs

    Hoarseness beyond 3 weeks combined with mouth or throat symptoms warrants urgent ENT input.

  • Non-healing extraction socket

    A tooth socket that fails to heal as expected after extraction can be an early sign of underlying bone or soft-tissue disease.

  • High-risk lifestyle plus any symptom

    Heavy tobacco and alcohol use alongside any of the above symptoms should lower the threshold for urgent referral.

Living with it

Support through treatment, and beyond it.

Four things that make the biggest difference through treatment and recovery - nutrition, speech and swallowing support, lifestyle change and consistent follow-up.

A quiet reminder

You are treated by a team, not alone.

Surgeons, oncologists, speech and language therapists and dietitians all work together on your plan.

  1. 01 Nutrition

    Work with a dietitian early

    Treatment can affect chewing, swallowing and taste - early dietetic input helps maintain weight and strength throughout.

  2. 02 Speech

    Speech and language therapy helps

    Swallowing and speech exercises before and after treatment improve function and confidence, especially after tongue surgery.

  3. 03 Habits

    Stop smoking, cut alcohol

    Quitting tobacco and reducing alcohol lowers the risk of recurrence and a second primary cancer, and supports healing.

  4. 04 Follow-up

    Keep every follow-up appointment

    Regular MDT follow-up catches recurrence early, when further treatment is most likely to succeed.

Frequently asked

Everything we get asked about mouth cancer.

Quick answers on symptoms, referral, diagnosis and treatment.

  • What is mouth cancer?

    Mouth cancer, or oral cancer, is a malignant growth affecting the lip, tongue, floor of mouth, gums or palate. The overwhelming majority are squamous cell carcinomas arising from the lining of the mouth.

  • What are the main risk factors?

    Tobacco use (smoked and smokeless), alcohol, HPV infection, betel quid chewing and poor oral hygiene. Tobacco and alcohol together carry a much higher risk than either alone, because they act synergistically.

  • How do I know if a mouth ulcer needs checking?

    Most mouth ulcers heal within 1 to 2 weeks. Any ulcer still present after 3 weeks, or one that is growing, hardening or bleeding, should be assessed by a GP or dentist without delay.

  • What does a 2-week-wait referral mean?

    It is an urgent NHS referral pathway under NICE NG12 for suspected cancer, guaranteeing an appointment with a specialist within 2 weeks so concerning symptoms are investigated quickly.

  • How is mouth cancer diagnosed and staged?

    Diagnosis is confirmed by biopsy of the suspicious area. CT, MRI or PET-CT scans are then used to stage the cancer, checking its size and whether it has spread to lymph nodes or elsewhere.

  • What treatment can I expect?

    Treatment is planned by a head and neck cancer MDT and may involve surgery with reconstruction, radiotherapy, chemotherapy, or a combination, alongside speech and language therapy and dietitian support.

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