Bowel cancer, also known as colon, rectal or colorectal cancer, occurs when abnormal cells grow uncontrollably…
- Mouth cancer occurs when cells of the mouth and the oral cavity (the cheeks, tongue, lips, gums and the roof and floor of the mouth) grow uncontrollably as a result of damage to their DNA.
- Risk factors for mouth cancer include smoking or chewing tobacco, drinking too much alcohol, poor mouth care and diet, and infection with some types of viruses.
- Mouth cancer can be treated by surgery and/or other types of therapy.
- The prognosis of mouth cancer can vary widely. It depends on the specific type of cancer you have, and on the stage it has progressed to.
What is mouth cancer?
Mouth cancer (also known as oral cancer) occurs when abnormal cells of the mouth and the oral cavity (the cheeks, tongue, lips, gums and the roof and floor of the mouth) grow uncontrollably.
Mouth cancers can invade local tissues and/or spread to other parts of the body (metastasise). Mouth cancers affect at least three Australians each day. 
The cause of mouth cancer, as with other cancers, is damage to cellular DNA. Within every cell in our bodies are control mechanisms that regulate the cells' growth, telling it when to multiply and when to stop multiplying. When the DNA of a healthy cell in a body changes (mutates) in such a way that these mechanisms are disrupted, the cell 'loses its brakes' and multiplies uncontrollably.The uncontrolled growth of cells leads to a tumour forming. The cancer cells can sometimes invade nearby tissues, or spread via the bloodstream or the lymphatic system to other areas of the body.
The exact cause of most mouth cancers is not well known, but certain factors can increase the risk of developing the condition.
Risk factors for mouth cancer include:
- Smoking cigarettes and tobacco use;
- Drinking alcohol;
- Poor oral hygiene and gum disease;
- Men are more commonly affected than women;
- Infection with human papilloma virus (HPV), Epstein-Barr virus (EBV) or herpes simplex virus (HSV);
- Family history: Having a sibling that has developed cancer in the head or neck almost doubles your risk;
- Habitually chewing the lips or the cheeks, or wearing ill-fitting dentures;
- A diet low in fruit and vegetables, and;
- Leukoplakia and erythroplakia: Leukoplakia is a light-coloured patch that develops on the side of the tongue or the inside of the mouth. Erythroplakia is a red, raised area that bleeds easily. Only a small number of people with leukoplakia go on to develop mouth cancer, but about half of people with erythroplakia do.
There are several types of mouth cancers, depending on the cells that give rise to the cancer.
Squamous cell carcinoma
Squamous cell carcinoma originates in the flat cells (known as squamous cells) that mainly line the insides of your mouth, nose and throat. This is the most common type of mouth cancer.
This is a rare type of cancer that develops in the glandular cells of the salivary glands and mouth.
This type of cancer originates in the cells of the skin that produce pigment. Most people think of melanoma as a disease of external skin, but it can also develop in internal areas such as the mouth and nose.
Lymphomas are cancers of the lymph nodes. There are many lymph nodes in the neck. Lymphomas can cause painless swelling of affected lymph nodes.
Stages of mouth cancer
Treatment outcomes can vary greatly depending on the stage of cancer. Cancer is staged according to the size and location of the cancer, and whether it has spread to nearby or distant lymph nodes throughout the body.
Cancerous cells that have not invaded healthy tissues.
The cancer is smaller than 2cm, and has spread deep into the lining of the tissue in the mouth, but not to nearby lymph nodes.
The cancer is 2-4cm in size and has not spread to lymph nodes.
The cancer is larger than 4cm, or has spread to a neighbouring lymph node.
The cancer has grown through the tissue around the lip and mouth, and may have spread to lymph nodes.
The cancer has spread to numerous lymph nodes.
The cancer has spread throughout the body to other organs.
Signs and symptoms
Signs and symptoms of mouth cancer include:
Methods for diagnosis
Medical history and physical examination
Your doctor will ask you questions about your medical history and your symptoms, and examine your mouth. If you have lesions (wounds or sores) in your mouth, your doctor may refer you to an ear, nose and throat specialist for further assessment.
Your doctor may ask for scans, such as ultrasound, computerised tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET), to help identify the exact type and characteristics of the lesion:
For this test, a narrow telescopic camera will be inserted into your throat in order to view it from the inside. You will be sedated during the procedure..
Removal of a tissue sample for examination under a microscope. A biopsy is the most accurate way of diagnosing a cancer.
Types of treatment
The cancer and affected lymph nodes may be surgically removed. There are many techniques for the surgical treatment of mouth cancers. The operation will depend on the location, size and number of lymph nodes affected by the cancer. Occasionally, after the removal of the cancer you may also benefit from plastic and reconstructive surgery that can restore your mouth's or nose's function and/or appearance. Your surgeon will discuss these surgical options with you.
Surgery is often combined with any of the following types of therapy:
Chemotherapy works by attacking cancer cells and stopping them from multiplying. Various drugs are used, which can be given intravenously or orally. They are often given in cycles: treatment for a few days, followed by a break that helps to reduce the treatment side effects.
In this type of therapy, focused X-rays from an external beam radiation source are applied to the area of the cancer. Radiotherapy helps to reduce the recurrence of cancers at their original site. It can occasionally be used on its own for the treatment of very small cancers (stages I or II).
The different types of therapies can be given either before or after surgery:
Adjuvant therapy is therapy that is given after surgery, with the aim of preventing the cancer from returning. It can take the form of radiotherapy, chemotherapy, or a combination of both.
Like adjuvant therapy, neoadjuvant therapy also takes the form of radiotherapy and/or chemotherapy, but is provided before surgery.
Mouth cancers are often treated by a team of health professionals including surgeons, oncologists (cancer specialists), radiation oncologists (radiation specialists), speech therapists, dietitians, psychologists and social workers. They help to prepare for treatment, coordinate therapies and assist in your rehabilitation. They are likely to review you periodically in the years following your treatment, to look out for any signs of the cancer recurring, and to assist in your recovery.
Some people diagnosed with cancer seek out complementary and alternative therapies. None of these alternative therapies are known to cure cancer, but some can help people feel better when used together with conventional medical treatment. It is important to discuss any treatments with your doctor before starting them.
Spread of cancer (metastasis)
Advanced mouth cancer can spread (metastasise) to other parts of the body through the bloodstream and lymphatic system.
Mouth cancer can cause difficulty in swallowing of some or all types of food and drinks. This is known as dysphagia. You may experience choking or coughing when swallowing, have a sensation that something is stuck in your throat, or bring food back up through the nose.
Treatment side effects
The side effects of treatment for mouth cancer include:
- Tooth loss - radiotherapy can destroy the jawbone (osteoradionecrosis), if decayed and loose teeth are left in place, so these need to be removed first;
- Need for prostheses - in some cases, part of the jaw may need to be removed and replaced by a prosthetic. In extreme cases, feeding tubes may have to be used because swallowing becomes too difficult;
- Damage to salivary glands - radiotherapy can damage the salivary glands, reducing the production of saliva, causing a dry mouth;
- Thyroid problems - radiotherapy can cause thyroid problems (hyper- or hypothyroidism) that require management with medication;
- Mouth infection - chemotherapy and radiotherapy of the mouth increase the risk of developing oral thrush;
- Nausea, vomiting and fatigue can be the result of chemotherapy and radiotherapy. Whether or not the treatment makes you feel sick is not an indication of how well the treatment is working;
- Altered bowel habits - constipation or diarrhoea can occur with chemotherapy;
- Joint and muscle pain can occur after a treatment session and can last a few days;
- Temporary hair loss in the head and body can occur after some forms of chemotherapy. The hair will grow back after treatment has ended, and;
- Tingling in the hands and feet - let your doctor know if this happens and they will adjust your chemotherapy.
Your prognosis will vary according to the specific type of cancer you have, and to the stage it has progressed to.
The five-year survival rate for mouth cancer in Australia, as of 2010, is between 67-93% from the time of diagnosis. 
It is important to remember that survival rates are only an indication; they are based upon the averages of previously treated patients. It is not a reflection of the prognosis for an individual. It is often difficult to accurately predict an individual's chance of cure or survival. Constant advances in treatment are continually improving the odds of cure and long-term survival from mouth cancer.
You can reduce your risk of getting mouth cancer by not smoking, minimising alcohol consumption, eating a healthy diet high in fruits and vegetables, and using protection during oral sex (HPV and HSV are sexually-transmitted viruses, so you can lower your risk of infection with these viruses by practising safe oral sex). Folate has been found to offer some protective effect against developing oral cancer.