What Is Mouth Cancer? What Causes Mouth Cancer? What Is Oral Cancer?

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Main Category: Ear, Nose and Throat
Also Included In: Dermatology;  Cancer / Oncology
Article Date: 25 Sep 2009 - 13:00 PDT

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Mouth cancer has the same meaning as oral cancer - it is cancer that occurs in any part of the mouth; on the tongue's surface, in the lips, inside the cheek, in the gums, in the roof and floor of the mouth, in the tonsils, and also the salivary glands.

Mouth cancer is a type of head and neck cancer, and is often treated similarly to other head and neck cancers.

34,000 Americans are diagnosed with oral or pharyngeal cancer each year, and about 8,000 die (annually). In England and Wales about 2,700 cases of oral cancer are diagnosed annually. Oral cancer kills approximately 920 people each year in England and Wales. Most oral cancer cases occur when the patient is at least 40 years old. It affects more men than women.

What are the signs and symptoms of oral cancer?

Most patients have no detectable symptoms during the early stages of oral cancer. Smokers, heavy drinkers should have regular checkups at the dentists' - dentists are often able to identify signs of oral cancer.

When signs and symptoms do appear, the typically include:

• Patches on the lining of the mouth or tongue, usually red or red and white in color.
• Mouth ulcers that do not go away.
• A sore that does not heal.
• A swelling in the mouth that persists for over three weeks.
• A lump or thickening of the skin or lining of the mouth.
• Pain when swallowing.
• Loosening teeth (tooth) for no clear reason.
• Dentures don't fit properly.
• Jaw pain.
• Jaw stiffness.
• Sore throat.
• A sensation that something is stuck in your throat.
• Painful tongue.
• A hoarse voice.
• Pain in the neck that does not go away.

If you have some of these symptoms you should see our doctor. There are many other conditions and diseases with similar symptoms.

What are the risk factors for mouth cancer?

A risk factor is anything that increases that likelihood of developing a disease or condition. For example, regular smoking increases the risk of developing lung cancer; therefore smoking is a risk factor for lung cancer. The risk factors for mouth cancer include:

• Smoking - studies indicate that a 40-per-day smoker has a risk five times great than a lifetime non-smoker of developing oral cancer.


• Chewing tobacco.


• Taking snuff (snorting tobacco).


• Both heavy and regular alcohol consumption - somebody who consumes an average of 30 pints of beer per week has a risk five times greater than a teetotaler or somebody who drinks moderately.


• Heavy smoking combined with heavy drinking - as tobacco and alcohol have a synergistic effect (their combined effect is greater than each one added together separately), people who drink and also smoke a lot have a significantly higher risk of developing oral cancer compared to others. Somebody who smokes 40 cigarettes per day AND consumes an average of 30 pints of beer a week is 38 times more likely to develop oral cancer compared to other people.


• Too much sun exposure on the lips, as well as sunlamps or sunbeds.


• Diet - people who consume lots of red meat, processed meat and fried foods are more likely to develop oral cancer than others.


• GERD (gastro-esophageal reflux disease) - people with this digestive condition where acid from the stomach leaks back up through the gullet (esophagus) have a higher risk of oral cancer.


• HPV (human papillomavirus) infection.


• Prior radiation treatment (radiotherapy) in the head and/or neck area.


• Regularly chewing betel nuts - these nuts, from the betel palm tree, are popular in some parts of south east Asia. They are slightly addictive and are also carcinogenic.


• Exposure to certain chemicals - especially asbestos, sulphuric acid and formaldehyde.

What causes oral cancer?

Cancer starts when the structure of the DNA (deoxyribonucleic acid) alters - a genetic mutation. DNA provides the cells with a basic set of instructions, much like a computer program for life. The instructions tell cells when to grow, reproduce, and die, among other things. When there is a genetic mutation cells grow in an uncontrollable manner, eventually producing a lump (tumor).

If the cancer is left untreated it grows and eventually spreads to other parts of the body, usually through the lymphatic system - a series of nodes (glands) that exist throughout the body. The lymph glands produce many of the cells of our immune system. As soon as the cancer reaches the lymphatic system it can spread anywhere in the body and invade bones, blood and organs. The cancer cells continue reproducing uncontrollably, gradually occupying more and more space.

Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and when this process breaks down, cancer begins to form. Unlike regular cells, cancer cells do not experience programmatic death and instead continue to grow and divide. This leads to a mass of abnormal cells that grows out of control.

With time, oral cancer may spread firstly to other parts of the mouth, then the head and neck, and eventually to other parts of the body. Mouth cancers typically start in the squamous cells (flat, thin cells) than line the lips and the inside of the mouth - they are referred to as squamous cell carcinomas.

Although we know what the risk factors are, experts are not sure what cause the mutations in squamous cells that eventually lead to mouth cancer.

How is mouth cancer diagnosed?

A GP (general practitioner, primary care physician) will carry out a physical examination and ask the patient questions about his/her symptoms. If oral cancer is suspected the patient will be referred to either an oncologist or an ENT (ear, nose and throat) specialist. An oncologist is a doctor who specializes in diagnosing and treating cancers. ENT specialists are also known as Otolaryngologists.

• Biopsy - the doctor may take a small sample of tissue to see if there are cancerous cells. In most cases the patient will be under general anesthetic. In some instances, just a local anesthetic is used, especially if the biopsy involves taking a sample from the surface of the tissue (fine needle aspiration biopsy).

As soon as mouth cancer is diagnosed the doctor will determine the extent (stage) of the cancer. Tests to help staging may include:

• Endoscopy - the doctor passes a lighted scope down the patient's throat to see whether the cancer has spread beyond the mouth.


• Imaging tests - the following tests may help the doctor determine whether the cancer has spread:
  
  
  • X-rays
  • Computerized tomography (CT) scans
  • Magnetic Resonance Imaging (MRI) scans
  • PET (positron emission tomography) scans

Staging the cancer (identifying its stage) provides a universally understood definition of a particular cancer's progress. It helps in the planning of treatment protocol for that particular cancer, helps in determining prognosis (predicting likely outcomes), and also allows accurate end-results reporting.

Stages of cancer of the lip and oral cavity

Stages of mouth cancer and lip cancer are indicated using Roman numerals from I to IV, with I being the smallest and IV the largest or most advanced.

• Stage I - the tumor is under 1 inch in diameter (2 cm) and has not reached nearby lymph nodes.


• Stage II - the tumor is over 1 inch in diameter (2 cm) but less than 2 inches (4 cm) and has not reached nearby lymph nodes.


• Stage III - any of the three possibilities below:
  
  • The tumor is over 2 inches (4 cm) in diameter.
  • The tumor has spread to just one nearby lymph node on the same side of the neck as the tumor.
  • The cancer in the lymph node is no more than 3cm.


• Stage IV - any of the possibilities below:
  • The cancer has reached tissues around the oral cavity and lip. Nearby lymph nodes may or may not contain cancer.
  • The cancer has spread to 2 or more lymph nodes on the same side of the neck as the tumor.
  • The cancer has spread to lymph nodes on the other side of the neck.
  • Lymph nodes on either side have a tumor that measures over 6 cm.
  • The cancer has spread further, to other parts of the body.

The TNM staging method

This is another method of staging mouth cancers. T describes the tumor, N describes the lymph node(s), and M describes metastasis (distant spread). X means there is no data to make an assessment.

• TX - not possible to assess primary tumor.
• T0 - there is no evidence of a primary tumor.
• Tis - carcinoma in situ (cancer only in the place where it began; it has not spread).
• T1 - tumor 2 cm maximum measurement in greatest dimension.
• T2 - tumor over 2 cm and 4 cm maximum in greatest dimension.
• T3 - tumor over 4 cm in greatest dimension. In the case of lip cancer, tumor invades adjacent structures, such as cortical bone, deep muscle of tongue, maxillary sinus, and skin.
• T4 - In the cases of oral cavity cancer, tumor invades adjacent structures, such as cortical bone, deep muscle of tongue, maxillary sinus, and skin.


• NX - nearby lymph nodes cannot be assessed.
• N0 - nearby lymph nodes have no cancer.
• N1 - cancer in one nearby lymph node on same side of neck. Maximum 3 cm in greatest dimension.
• N2
  • N2a - cancer has spread to one lymph node on same side of neck, no more than 6 cm in greatest dimension.
  • N2b - Cancer has spread to 2 or more lymph nodes; none are greater than 6 cm in greatest dimension.
  • N2c - Cancer has spread to lymph nodes on either side of the neck, or both sides of the neck, no bigger than 6 cm in greatest dimension.
• N3 - cancer has spread to a lymph node and is over 6 cm in greatest dimension.


• MX - distant metastasis (spread) cannot be assessed.
• M0 - no distant metastasis.
• M1 - distant metastasis.

Therefore if a patient is described as T2N1M0, it means:

There is a primary tumor between 2 cm and 4 cm, it has spread (metastasized) to one single lymph node on one side, that node is less than 3 cm in size, there is no distant metastasis.

What are the treatment options for mouth (oral) cancer?

Treatment will depend on various factors, such as where the cancer is, its stage, as well as the patient's general health and personal preferences. Some people may have to undergo a combination of treatments.

Surgery - this may include:

• Surgical removal of the tumor - the tumor is surgically taken out, as well as a margin of healthy tissue around it. If the tumor is small surgery will be minor. Larger tumors will require more extensive surgery, such as the removal of some of the jawbone or some of the tongue.


• Surgical removal of cancer that spread to the neck - mouth cancer tends to spread to the lymph nodes in the neck. The surgeon may perform a neck dissection - cancerous lymph nodes and related tissue in the neck are surgically removed. A radical neck dissection involves the removal of a tumor from the neck as well as additional normal tissue of at least 2 cm surrounding the tumor, as well as removing the lymph nodes from the neck. In a radical dissection not only is the affected tissue removed, but also nearby tissue that may be affected (but not clearly identified as such).


• Mouth reconstruction - if surgery significantly changed the appearance of the face, or the patient's ability to talk and/or eat, surgeons may transplant grafts of skin, muscle or bone form other parts of the body to reconstruct the face. To help in eating, implants may replace the patient's natural teeth.

Radiotherapy (radiation therapy) - about 40% of all types of cancer patients undergo some kind of radiotherapy. It involves the use of beams of high-energy X-rays or particles (radiation) to destroy cancer cells. Radiotherapy works by damaging the DNA inside the tumor cells, destroying their ability to reproduce. Radiation therapy can be delivered from outside the body (external beam radiation) or from radioactive seeds and wires that are placed near the cancer inside the body (brachytherapy). Oral cancers are especially sensitive to radiotherapy.

Internal radiotherapy (brachytherapy) - often used to treat patients with early stages of cancer of the tongue. Radioactive wires or needles are stuck directly into the tumor while the patient is under a general anesthetic. The wires/needles release a dose of radiation into the tumor. While the patient is receiving internal radiation therapy he/she will stay in a single room at the hospital. Although levels of radiation are generally safe, hospital staff will only be able to spend short periods in the same room during treatment. This is because staff members are dealing with radiation every day of their lives and their exposure, although small each time, can accumulate over the long-term.

Most courses of brachytherapy last from 1 to 8 days.

The patient's mouth will swell and he/she will have some pain five to ten days after the implants are taken out. Within a few weeks the pain will ease and go away. Patients may find that consuming cool, plain, soft foods is easier. Smoking tends to make the pain worse.

Individuals in early-stage mouth cancer may be fortunate enough to have radiation therapy as their only treatment.

Radiation therapy is often used before and after surgery. It is usually given after surgery to help prevent recurrence (cancer coming back). It is sometimes used in combination with chemotherapy.

For those with advanced cancer radiation therapy may help relieve pain.

Radiation therapy applied to the mouth may have the following side effects:

• Tooth decay
• Mouth sores
• Bleeding gums
• Jaw stiffness
• Fatigue
• Skin reactions (similar to burns)

Chemotherapy - When the cancer is widespread chemotherapy is commonly used with radiotherapy. If there is a significant risk of recurrence (cancer coming back) chemotherapy combined with radiotherapy may be used.

Chemotherapy involves using powerful medicines that kill cancer; they damage the DNA of the cancer cells, undermining their ability to reproduce. Chemotherapy medications can sometimes damage healthy tissue, and patients may experience the following side-effects:

• Fatigue
• Vomiting
• Nausea
• Hair loss
• Weakened immune system (higher vulnerability to infection)

As soon as treatment is over side effects usually go away.

Targeted drug therapy (monoclonal antibodies) - this involves drugs that change aspects of cancer cells that help them grow. Cetuximab (Ebitux) is used for some head and neck cancers - it stops the action of a protein found in many kinds of healthy cells, but is more prevalent in the surface some cancer cells. The protein is called epidermal growth factor receptors (EGFR).

Sometimes targeted drugs are used in combination with radiotherapy or chemotherapy.

Cetuximab is given through a drip into the vein over a period of a few hours during the first administration - subsequent weekly doses take about an hour each.

Cetuximab may have the following mild side effects:

• Nausea
• Diarrhea
• Breathlessness
• Inflammation of the eyes (conjunctivitis)

Some patients may have an allergic reaction to cetuximab, such as a swollen tongue or throat. Sometimes these allergic reactions may be severe and life-threatening (an infusion reaction). Most infusion reactions will occur within 24 hours of receiving treatment - it is important that patients are monitored closely. Approximately 3% of those receiving cetuximab have an infusion reaction.

The medical team

In the UK and many other countries a large medical team (multi-disciplinary team, or MDT) will be involved in the treatment of a person with mouth cancer. A typical team may include:

• A clinical oncologist
• A clinical specialist nurse (nurse specialized in oral cancer)
• A dentist
• A dietician/nutritionist
• A pathologist
• A radiologist
• A social worker
• A speech and language therapist
• A surgeon

What are the complications of oral (mouth) cancer?

• Difficulty swallowing (dysphagia) - for most of us swallowing is an automatic process which we take for granted. Patients with oral cancer, especially those who have undergone surgery and/or radiotherapy may find that the procedures affected their tongue, mouth or throat.
  
  Apart from the risk of malnutrition, dysphagia can result in food going down the wrong way, chocking, and lung infections (aspiration pneumonia).
  
  A speech and language therapist (SLT) can assess a patient's swallowing ability via a test called videofluoroscopy. A special dye is added to solid foods and liquids which the patient swallows. The SLT can study the patient's swallowing reflexes with X-rays and determine whether any particles of solids or liquids are entering the lungs. If this is so, a short-term feeding tube may be directly connected to the patient's stomach. The patient will then learn exercises that improve his/her swallowing. Swallowing exercises will have a beneficial effect over time. Unfortunately, in some cases the patient never fully recovers his/her ability to swallow properly. A nutritionist may help these patients by recommending specific foods that are easier to swallow properly.


• Speaking problems - radiotherapy and/or surgery can interfere with the processes involved in speaking, making it harder for the patient to utter specific sounds, or series of sounds properly. A SLT can help improve the patient's verbal skills by teaching some exercises that develop vocal movements. The SLT can also teach the patient how to produce sounds in different ways.


• Depression - coping with cancer, its treatments, not knowing what your long-term prospects are, pain, swallowing difficulties, speech problems, etc., can bear down on the patient, making them irritable, frustrated, anxious and depressed. If is important that you tell somebody in your medical team if you are finding it difficult to cope mentally or/and emotionally. Joining a support group, if there is one in your area, has helped many people - meeting people who share some of your experiences can help.

Prevention

• Tobacco - smoking, chewing and snorting (snuff) tobacco increases the risk of developing oral cancer. Therefore, quitting helps lower your risk.


• Alcohol - if you drink a lot, cut down or give up. If you stay within the recommended guidelines for alcohol consumption, or stop drinking completely, your risk of developing oral cancer will drop significantly.


• Diet - a diet high in fruit, vegetables, fish oil, olive oil, combined with moderate quantities of lean animal or plant-based protein, as well as whole grains, will lower your risk of developing oral cancer. Cut out all junk foods, saturated fats, and processed meats.


• Sun exposure - avoid excessive sun exposure to your lips. Some sun is good for you, too much is bad for your skin and lips. Apply a sunscreen lip product.

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today