Mouth cancer, or oral cancer can occur anywhere in the mouth, on the surface of the tongue, the lips, inside the cheek, in the gums, in the roof and floor of the mouth, in the tonsils, and in the salivary glands.
It is a type of head and neck cancer and is often treated similarly to other head and neck cancers.
Mouth cancer mostly happens after the age of 40 years, and the risk is more than twice as high in men as in women.
Signs and symptoms
Oral cancer can appear as a lesion or tumor anywhere in the mouth.
In the early stages, there are often no signs or symptoms, but smokers and heavy drinkers should have regular checkups with the dentist, as they may identify early signs.
Signs and symptoms include:
- Patches on the lining of the mouth or tongue, usually red or red and white in color
- Mouth ulcers or sores that do not heal
- Swelling that persists for over 3 weeks
- A lump or thickening of the skin or lining of the mouth
- Pain when swallowing
- Loose teeth with no apparent reason
- Poorly fitting dentures
- Jaw pain or stiffness
- Sore throat
- A sensation that something is stuck in the throat
- Painful tongue
- Hoarse voice
- Pain in the neck that does not go away
Having any of these symptoms does not mean that a person has mouth cancer, but it is worth checking with the doctor.
Causes and risk factors
Cancer results when a genetic mutation instructs cells to grow without control. Untreated, oral cancer will start in one part of the mouth, then it spreads to other parts of the mouth, to the head and neck and the rest of the body.
Mouth cancers typically start in the squamous cells that line the lips and the inside of the mouth. This is called squamous cell carcinoma.
The exact cause of the mutations is unknown, but there is evidence that certain risk factors increase the chance of mouth cancer developing.
Tobacco and alcohol use are important risk factors for mouth cancer.
Smokers are three times more likely than nonsmokers to develop mouth cancer, and people who smoke and drink alcohol have up to 30 times higher risk than those who do not smoke and drink.
Smoking is a significant risk factor for mouth cancer.
Other risk factors include:
- Sun exposure on the lips, from the sun, sunlamps or sunbeds
- A diet rich in red meat, processed meat, and fried foods
- Gastro-esophageal reflux disease GERD, a digestive condition where acid from the stomach leaks back up through the gullet
- Human papillomavirus (HPV) infection
- Prior radiation treatment, or radiotherapy, in the head, neck, or both
- Regularly chewing betel nuts, a popular habit in some parts of south-east Asia
- Exposure to certain chemicals, especially asbestos, sulfuric acid and formaldehyde
The United Kingdom's National Health Service (NHS) note that there is a "small chance" that broken or jagged teeth increase the risk of mouth cancer. They encourage people to follow good oral and dental hygiene practices, including regular brushing, to reduce the risk.
A dentist may be the first person to notice that something is wrong. They may advice the patient to doctor see a doctor, who will examine the patient and ask about symptoms. If they suspect oral cancer, the patient will be referred to a specialist.
The dentist may be the first person to spot signs of mouth cancer.
A biopsy may be carried out, where a small sample of tissue is taken to check for cancerous cells.
If mouth cancer is diagnosed, the next task is to determine the stage of the cancer.
- Endoscopy, where a lighted scope is passed down the patient's throat to see how far the cancer has spread
- Imaging tests, such as x-ray, CT scans, and MRI
Staging the cancer will inform treatment options and help predict prognosis.
There are different methods of staging oral cancer. One common way is by numbers, is on a scale of one to four.
- Stage I: The tumor is under 1 inch across and has not reached nearby lymph nodes
- Stage II: The tumor measures 1 to 2 inches, and it has not reached nearby lymph nodes
- Stage III: Either the tumor is over 2 inches across but has not spread; or it has spread to one nearby lymph node on the same side of the neck as the tumor, and the lymph node is no more than 1 inch across
- Stage IV: The cancer affects tissues around the mouth, lips and possibly nearby lymph nodes; or it has spread to two or more lymph nodes on the same side of the neck as the tumor; or it has spread to lymph nodes on the other side of the neck; or lymph nodes on either side have a tumor that measures over 2 inches; or the cancer has spread to other parts of the body.
A person who is diagnosed with Stage I oral or pharyngeal cancer has an 83 percent chance of surviving for longer than 5 years. Around 31 percent of cases are diagnosed at this stage.
For those whose cancer spreads to other parts of the body, the chance of surviving more than 5 years is 38 percent.
Treatment depends on the location and stage of the cancer, and the patient's general health and personal preferences. A combination of treatments may be necessary.
Surgical removal of the tumor involves taking out the tumor and a margin of healthy tissue around it. A small tumor will require minor surgery, but for larger tumors, surgery may involve removing some of the tongue or the jawbone.
If the cancer has spread to the lymph nodes in the neck, the cancerous lymph nodes and related tissue in the neck will be surgically removed.
If surgery significantly changes the appearance of the face, or the patient's ability to talk, eat, or both, reconstructive surgery may be necessary, using transplanted grafts of skin, muscle or bone form other parts of the body. Dental implants may be needed.
Oral cancers are especially sensitive to radiation therapy, which uses beams of high-energy x-rays or radiation particles to damage the DNA inside the tumor cells, destroying their ability to reproduce.
External beam radiation delivers radiation from outside, while in brachytherapy, radioactive seeds and wires can be placed near the cancer inside the body.
Brachytherapy is often used to treat patients with early stages of cancer of the tongue.
Radioactive wires or needles are stuck directly into the tumor, and these release a dose of radiation into the tumor. The patient is normally under general anesthetic. A course normally lasts from 1 to 8 days.
The patient's mouth will swell, and there will be some pain for 5 to 10 days after removing the implants. The pain will gradually disappear over the next weeks. Consuming cool, plain, soft foods may help, but smoking normally increases discomfort.
A person with early-stage mouth cancer may only need radiation therapy, but it can also be combined with surgery, chemotherapy, or both, to prevent the cancer from returning.
Radiation therapy may remove cancer if a patient is in the early relieve pain in advanced oral cancer.
Adverse effects of radiation therapy in the mouth include:
- Tooth decay
- Mouth sores
- Bleeding gums
- Jaw stiffness
- Skin reactions, as with a burn
Widespread cancer may be treated with chemotherapy as well as radiation therapy, especially if there is a significant chance of the cancer returning.
Chemotherapy, radiotherapy, and surgery are three treatment options.
Chemotherapy involves using powerful medicines that damage the DNA of the cancer cells, undermining their ability to reproduce.
Chemotherapy medications can sometimes damage healthy tissue.
The following adverse effects may occur:
- Hair loss
- Weakened immune system, increasing the risk of infection
These effects usually go away after finishing treatment.
Targeted drug therapy
Targeted drug therapy uses drugs known as monoclonal antibodies to change aspects of cancer cells that help them grow.
Cetuximab, or Erbitux, is used for some head and neck cancers. It stops the action of a protein that occurs in healthy cells, but is more prevalent in some cancer cells. The protein is called epidermal growth factor receptors (EGFR).
Targeted drugs may be combined with radiotherapy or chemotherapy.
The first dose of Cetuximab is given intravenously over a period of a few hours, and subsequent weekly doses take about an hour each.
The following mild adverse effects are possible:
Around 3 percent of patients will have an allergic reaction to cetuximab, such as a swollen tongue or throat. This will normally occur within 24 hours of treatment. It can be severe and life-threatening, so patients should be monitored.
ComplicationsComplications include difficulty swallowing, or dysphagia. Swallowing is normally an automatic process, but surgery or radiotherapy may affect the action of the tongue, mouth or throat.
If tests show that particles of food are entering the patients' lungs, a short-term feeding tube may be directly connected to the stomach, while the patient learns exercises that improve their swallowing. A person who continues to have problems may need to follow a special diet.
Speaking problems are common, but a speech therapist can teach some exercises that develop vocal movements.
A number of lifestyle changes can reduce the risk of mouth cancer.
- Quitting or avoiding tobacco
- Consuming alcohol in moderation or not at all
- Avoid excessive sun exposure and using sunscreen on the lips
- Avoiding junk foods, saturated fats, and processed meats
Evidence suggests that the chance of developing cancer is lower among those who exercise regularly and follow a healthy diet, with plenty of fruit, vegetables, fish oil, olive oil, whole grains, and small amounts of lean animal or plant-based protein.