Skip to main content


This information should not be used for self-diagnosis or in place of a qualified physician's care.

Reviewed Nov 2020

The basics
  • Guidelines for treating this cancer are treated by members of BC Cancer's Head and Neck Tumour Group.
  • For health professional information on treating this cancer, please see our Cancer Management Guidelines.
  • Mouth cancer may also be called oral cancer, oral cavity cancer, tongue cancer, or lip cancer.
  • The mouth or oral cavity includes: the lips, gums, the front two thirds (the mobile part) of the tongue, the hard palate, the floor of the mouth, the lining of the cheeks, and the salivary glands.
  • The mouth is necessary for talking, eating, chewing, and swallowing. Salivary glands make the saliva that moistens the mouth and helps digest food.
What causes it and who gets it?

Listed below are some of the known causes of this cancer. Not all of the risk factors below may cause this cancer, but they may be contributing factors. 

  • Tobacco use in any form increases risk of developing mouth cancer. The longer tobacco has been used, the greater the risk.
  • Heavy drinking in those who do not smoke increases the risk for mouth cancer.
  • Drinking alcohol in combination with tobacco use greatly increases the risk of mouth cancer.
  • Passive smoking (spending time in a smoking environment, or living with a smoker) increases risk.
  • Long-term unprotected exposure to strong sunlight increases the risk of lip cancer.
  • Chewing betel or areca nuts (found in paan, chaalia, gutka and naswar) increases the risk of mouth cancer.
  • A diet low in fruits and vegetables increases the risk of mouth cancer.
  • Chronic irritation from poorly-fitted dentures may increase the risk.
  • Chronic gum disease (periodontal disease) may increase the risk of tongue cancer.
  • Infection with human papillomavirus may increase risk of developing mouth cancer.
  • Statistics:
    NOTE:  Available statistics do not have information about the inclusion of transgender and gender diverse participants. It is unknown how these statistics apply to transgender and gender diverse people.  Patients are advised to speak with their primary care provider or specialists about their individual considerations and recommendations.
Can I help to prevent it?

Most mouth cancers can be prevented. Tobacco and alcohol use are the major risk factors for developing mouth cancer. 

  • To reduce your risk, don’t smoke, and avoid exposure to tobacco and cigarette smoke. Even if you have been using tobacco for many years, quitting will reduce your cancer risk. Support is available to help you successfully quit. Visit BC Cancer’s Prevention page on Tobacco for information and resources. 
  • Avoid excessive use of alcohol. Not drinking at all will reduce your cancer risk the most. 
  • Patients who are cured of mouth cancer are more likely to develop a second cancer if they continue to use tobacco and alcohol. Even if you are diagnosed with a mouth cancer, quitting tobacco and alcohol can reduce the possibility of the cancer returning.
  • If you work outdoors, use sunscreen on your lips, and protect your face by wearing a broad-brimmed hat. 
  • Eating healthy, nutritious foods can reduce your cancer risk. Follow the recommendations in Canada's Food Guide and visit the BC Cancer’s Prevention page on Nutrition for information and resources. In particular, eating plenty of fruits and vegetables can reduce your risk for this cancer.
  • Visit your dentist regularly.

Screening for this cancer

  • Regular dental checkups, including a full-mouth exam are the best method of screening for mouth cancers.
  • BC Cancer's Oral Cancer Prevention Program works with dentists and dental hygienists to prevent the development of oral cancer, and to detect it at the earliest possible stage.
Signs and Symptoms
  • Your dentist will check your mouth for these signs during your regular visits. If any of the following symptoms last for more than two weeks, visit a dentist or doctor.
  • The most common symptom is an ulcer or sore or swelling in the mouth that doesn't heal.
  • A lump, thickening or rough spot in the mouth that doesn't go away or seems to be growing.
  • The appearance of different coloured spots in the mouth or lips. They may also feel different.
    • White spots are known as leukoplakia.
    • Red coloured spots are called erythroplakia.
  • Pain, numbness, tenderness of the lips, mouth jaw or ear.
  • Chewing or swallowing difficulties.
  • A change in the way your teeth fit together.
  • A change in your voice.
Diagnosis & staging


These are tests that may be used to diagnose this type of cancer.

  • A biopsy, which is the removal of a small bit of tissue for examination in a laboratory, is the usual first step in diagnosing mouth cancers.
  • A diagnostic imaging examination may be recommended depending on biopsy results. This could include:
    • CT - computed tomography.
    • MRI - magnetic resonance Imaging.
    • PET - positron emission tomography.

For more information on tests used to diagnose cancer, see our Recommended Websites, Diagnostic Test section.

Types and Stages


  • The most common type of mouth cancer is squamous cell carcinoma, occurring in the cells that line the mouth.
  • Adenocarcinomas, sarcomas and melanomas can also occur.


Staging describes the extent of a cancer. The TNM classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.

T describes the site and size of the main tumour (primary)
describes involvement of lymph nodes
relates to whether the cancer has spread (presence or absence of distant metastases)

Stage T1 
The tumour is 2 cm or less in greatest dimension.  

Stage T2 
The tumour is more than 2 cm, but not more than 4 cm in diameter.  

Stage T3
The tumour is more than 4 cm in greatest dimension.  

Stage T4
Lip - The tumour has invaded adjacent structures.

Oral cavity - The tumour has invaded adjacent structures, eg. into bone, or the deep muscles of the tongue, or skin of the face. 

Stage T4b
The tumour has invaded the skull base, or encases the carotid artery. 



Cancer therapies can be highly individualized – your treatment may differ from what is described below.

  • Case-by-case treatment decisions are made for each patient, based on the specific site of the tumour, the extent of the disease and the patient's overall general condition.
  • Localized oral tumours are usually removed through surgery or laser excision.
  • Early stage tumours are treated with either surgery or radiotherapy.
  • Surgery is usually chosen for tumours that can be removed with a good functional result.
    • Mouth cancer surgery may remove underlying bone and may require reconstruction with skin, muscle and/or bone taken from other areas of the body.
  • Radiotherapy is preferred when surgery would require major reconstruction. Radiotherapy options can include radioactive implants (which treat only the primary site) or external beam irradiation (which can treat both the primary tumour and nearby lymph nodes). External beam therapy is given on an outpatient basis and usually lasts between two and five weeks.
  • Clinically advanced tumours are often treated with both surgery and radiation.
  • Some cancers have a high risk of microscopic spread to neck nodes and if the risk is high, the neck may be irradiated even if there is no definite evidence of tumour spread to the lymph nodes.
  • Prognosis is fairly good for patients diagnosed with an oral cancer. BC Cancer survival statistics show that 62% of total patients diagnosed with mouth cancer in 2003, survived at least 5 years. Survival statistics must be viewed with caution, and should not be used to predict individual response to treatment.

Follow-up after Treatment 

  • Guidelines for follow-up after treatment are covered on our website.
  • You will be returned to the care of your family physician or specialist for regular follow-up. If you do not have a family physician, please discuss this with your BC Cancer oncologist or nurse.
  • Follow-up testing is based on your type of cancer and your individual circumstances.
  • Excellent oral hygiene must be maintained. Detailed information about the effects of radiation on teeth is available in the Head and Neck Cancer Management Guidelines.
  • Life after Cancer focuses on the issues that cancer survivors can face.
Tab Heading
SOURCE: Mouth ( )
Page printed: . Unofficial document if printed. Please refer to SOURCE for latest information.

Copyright © BC Cancer. All Rights Reserved.

    Copyright © 2021 Provincial Health Services Authority