What is throat cancer?

Throat cancer occurs when abnormal cells grow uncontrollably in the throat. Cancer can develop in any of the three different parts of the throat:

  • Nasopharynx - behind the nose, at the upper part of the throat;
  • Oropharynx - the middle part of the throat, at the back of the tongue region, and;
  • Laryngopharynx - the lower part of the throat near the voice box and oesophagus. 

Anatomy of the throat. 

Causes

The cause of throat cancer, as with other cancers, is due to damage to cellular DNA. This results in uncontrolled growth of damaged cells, which leads to the formation of a cancer. The cancer can invade nearby tissues, or spread via the bloodstream or lymphatic system to other areas of the body.

The exact cause of throat cancers is not well known. However, certain risk factors are known to increase the risk of developing this condition.

Lymphatic system

A network of vessels, lymph nodes, the spleen and other organs that transport lymph fluid between tissues and bloodstream.

Risk factors

Risk factors for throat cancer include:

Smoking and tobacco use

Smokers are three to four times more likely to develop a nasopharyngeal cancer than non-smokers. The risk of developing this cancer depends on how much you smoke and how long you have smoked for. Even if you only smoke pipes or cigars, or chew tobacco, you still have an increased risk of developing throat cancers.

Excessive alcohol intake

Regular alcohol consumption greatly increases the risk of developing throat cancer, but smoking at the same time increases this risk several-fold.

Infection

An infection with human papilloma virus (HPV), Epstein-Barr virus (EBV) or herpes simplex virus (HSV) increases your risk of developing throat cancers. HPV and HSV are sexually transmitted viruses, therefore the risk of infection with these viruses can be reduced by practising safe oral sex.

HIV/AIDS

If you have HIV/AIDS, you have double the risk of developing nasopharyngeal cancer.

Poor diet

A diet low in fruit and vegetables increases your risk. Folate has been found to have a protective effect against throat cancer.

Epstein-Barr virus

A virus of the herpes family that causes mononucleosis, also known as mono or glandular fever. It is also implicated in some other medical conditions.

Folate

A type of vitamin B involved in the creation of DNA and RNA. It plays a key role in cell growth and reproduction.

HIV

A virus transmitted mainly by sexual or blood-to-blood contact, that infects cells of the immune system. It is the causative agent of acquired immune deficiency syndrome (AIDS).

HPV

A virus with many subtypes that cause warts, including common warts of the hands and feet, and genital warts. Some strains of HPV cause cervical cancer.

Types

The type of cancer can be classified by the type of cells, the cancer develops in:

Squamous cell carcinoma

Squamous cell carcinoma originates in the squamous cells, which are flat cells that line the inside of the mouth, nose and throat. The vast majority of nasopharyngeal and oropharyngeal cancers are squamous cell carcinomas. 

Adenocarcinoma

Adenocarcinoma is a rare type of cancer that develops in the glandular cells of the throat.

Sarcoma

Sarcomas are cancers of the body's connective tissue and are extremely rare in the throat. The connective tissue of the larynx is cartilage. The name for a cancer that originates in the cartilage is chondrosarcoma.

Lymphoma

Lymphomas are cancers of the lymph nodes. There are many lymph nodes in the neck and lymphomas can cause painless swelling of these lymph nodes.

Cartilage

A tough, flexible connective tissue found in various parts of the body including the joints and larynx.

Glandular cells

Specialised cells that secrete materials such as lubricants and hormones.

Lymph nodes

A small organ of the lymphatic system containing many immune cells. Lymph nodes, also known as lymph glands, are the sites where many interactions between immune cells and foreign materials occur.

Stages

Treatment outcomes can vary greatly, depending on the stage of the cancer. Cancer is staged according to the size and location of the primary cancer and whether it has spread to lymph nodes or organs in the body.

Stages of nasopharyngeal cancer

Stage 0

This stage is also known as carcinoma in situ. It is when abnormal cells are found, but they have not yet become cancerous or spread beyond the place they first appeared.

Stage I

The cancer is in the nasopharynx only, or has spread to the middle part of the back of the throat (oropharynx) and/or nasal cavity.

Stage II

The cancer is in the nasopharynx only, or has spread to the middle part of the back of the throat (oropharynx) and/or the nasal cavity and to local lymph nodes. Also includes a tumour that has spread to the connective tissue that fills the space in the jaw bone at the base of the skull and includes one or more local lymph nodes.

Stage III

Stage III cancer is found in the same areas as Stage II cancer but has spread to lymph nodes on both sides of the neck or the cancer has spread to nearby sinuses and bone.

Stage IVA

The cancer is within the skull and may affect its nerves, the eyes, nearby tissue or the throat. The cancer might have spread to lymph nodes on both sides of the neck, but they are above the collarbone and not greater than six centimetres.

Stage IVB

The tumour might have grown into nearby tissue or bone. It has also spread to at least one lymph node greater than six centimetres, or to the collarbone, or both.

Stage IVC

The cancer has spread to distant sites in the body.

 

Stages of oropharyngeal cancer

Stage 0

This stage is also known as carcinoma in situ. It is when abnormal cells are found, but they have not yet become cancerous or spread beyond the place they originated.

Stage I

The tumour is less than two centimetres diameter and has spread deep into the lining of the tissue in the mouth or oropharynx, but not to nearby organs or lymph nodes.

Stage II

The tumour is two to four centimetres in diameter and has not spread to lymph nodes or organs.

Stage III

The tumour is greater than four centimetres in diameter, but has not spread to lymph nodes or organs; or the tumour is any size and has spread to a single lymph node on the same side of the neck the tumour is located.

Stage IVA

The tumour has grown through the tissue around the lip and mouth and may have spread to lymph nodes in the area.

Stage IVB

The tumour is any size and the cancer has spread to multiple lymph nodes on the same side of the neck as the tumour; or to both sides of the neck; or to any lymph node greater than six centimetres in size.

Stage IVC

The cancer has spread throughout the body to distant organs.

 

Stages of laryngopharyngeal cancer

Stage 0

This stage is known as carcinoma in situ. It is when abnormal cells are found, but they have not yet become cancerous or spread beyond the place they originated.

Stage I

The tumour is only in one section of the throat and doesn't affect the vocal cords.

Stage II

The tumour is on, above, or below the vocal cords, but isn't affecting the normal movement of the vocal cords and the cancer has spread to another part of the larynx.

Stage III

The tumour has spread throughout the larynx, but hasn't spread further than the covering of the larynx and one or more vocal cords can't move.

Stage IV

The cancer has spread beyond the larynx to the thyroid gland, windpipe or oesophagus, or to distant organs.

Lymph nodes

A small organ of the lymphatic system containing many immune cells. Lymph nodes, also known as lymph glands, are the sites where many interactions between immune cells and foreign materials occur.

Signs and symptoms

Signs and symptoms of throat cancer may include:

  • A sore throat;
  • Cough;
  • Pain or difficulty swallowing;
  • Pain in the ear;
  • Unexpected weight loss;
  • A lump in the back of the mouth or throat, and;
  • Bloody sputum.

Sputum

Mucus and possibly pus, bacteria and blood that is coughed up from the airways, typically as a result of an infection.

Methods for diagnosis

Medical history and physical examination

Your doctor will ask you questions about your medical history, any symptoms you have and possible risk factors. If your doctor has any concerns, you'll be referred to an ear, nose and throat specialist for further examination, investigation and management. 

Scans

Barium swallow

A barium swallow involves drinking a chalky substance that contains barium, followed by an X-ray or scan. This may be the first test performed if one of the symptoms is having trouble swallowing. The swallow can show a narrowing of the throat or a protrusion that are due to a mass in the throat.

Computerised tomography (CT) scan

A computerised tomography scan uses X-rays to develop a 3D image of the body. This type of scan can detect small cancers much more effectively. The scan may be used to identify the original site of the cancer and to establish the spread of the cancer within the head or neck area or to other more distant sites.

Magnetic resonance imaging (MRI)

Magnetic resonance imaging is a 3D scan similar to CT, but uses magnetism instead of X-rays. An MRI scan is often peformed when more detailed images of the cancer are required.

Positron emission tomography (PET)

Positron emission tomography requires an injection with a radioactive label, or tracer. When combined with a CT scan, it produces images that can help assess the size, location and spread of a cancer.

Procedures

Upper endoscopy

During an upper endoscopy, you will be sedated and a slender telescopic tube will be inserted into your nose and throat. A tissue biopsy may be performed during this procedure if an abnormal lesion is found.

Laryngoscopy

During a laryngoscopy, your voice box will be checked for abnormalities using a laryngoscope, a slender tube with an attached camera. The doctor will usually apply an anaesthetic spray to numb your throat before the procedure. 

Biopsy

A biopsy is a removal of a tissue sample for examination under a microscope. The biopsy is the only definite way of making a cancer diagnosis as it provides the most accurate analysis of the abnormal-looking cells. 

Anaesthetic

A medication or other substance that causes a temporary loss of sensations, including pain.

Types of treatment

Surgery

The cancer and affected lymph nodes may be surgically removed. They are numerous different techniques for the surgical treatment of throat cancers, depending on the location, size and lymph nodes affected. Occasionally, reconstructive surgery may also be necessary to restore function and/or appearance, after the removal of the cancer. Your surgeon can help discuss surgical options with you. Surgery is often combined with adjuvant and/or neoadjuvant therapy for better outcomes. 

Adjuvant therapy

Adjuvant therapy is given after surgery, with the aim of preventing the cancer from returning. It can take the form of radiotherapy and/or chemotherapy.

Neoadjuvant therapy

Like adjuvant therapy, neoadjuvant therapy also uses radiotherapy and/or chemotherapy, but is provided before surgery.

Chemotherapy

Chemotherapy works by attacking cancer cells and stopping their reproduction. Various medications are used, which are generally administered intravenously. They are often given in cycles, followed by rest periods, which help to reduce the toxic side effects of chemotherapy. Your doctor will monitor your dosage and treatment schedule to ensure optimal therapeutic dosage is administered, with minimum side effects.

Some of the drugs used in chemotherapy are administered via an IV.Various medications are used in chemotherapy to treat cancer. 

Radiotherapy

In this type of therapy, focused X-rays from an external beam radiation source are applied to the area where the cancer was located. 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. Commonly, it is combined with surgery as adjuvant and/or neoadjuvant therapy. 

Multi-disciplinary treatment

Throat cancers are often treated by a group of health professionals including surgeons, oncologists (cancer specialists), radiation oncologists (radiation specialists), speech therapists, dieticians, psychologists and social workers. The team of health professionals help to prepare for treatment, coordinate therapies and assist in rehabilitation. They can be contacted for any assistance during the treatment process. They are likely to regularly review you in the years following your treatment to detect any cancer recurrence and assist you in your recovery.  

Other therapies

Some people diagnosed with cancer seek out complementary and alternative therapies. None of these alternative therapies 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.

Lymph nodes

A small organ of the lymphatic system containing many immune cells. Lymph nodes, also known as lymph glands, are the sites where many interactions between immune cells and foreign materials occur.

Potential complications

Treatment side effects

Side effects associated with treatments include:

  • Speech problems - radiotherapy and surgery can affect your ability to speak normally due to the damage they cause to the tissues supporting the voice box. Modulating the intensity of the treatment can reduce the damage to surrounding tissues; 
  • Tooth loss - radiotherapy can destroy the jawbone (osteoradionecrosis) if bad or loose teeth are present, so these need to be removed before using this type of therapy;
  • 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 is too difficult;
  • Damage to salivary glands - radiotherapy can damage the salivary glands, reducing the production of saliva and causing dry mouth (xerostomia);
  • Thyroid problems - radiotherapy can cause thyroid problems (hyperthyroidism or hypothyroidism) that require management with medication;
  • Throat infection - chemotherapy and radiotherapy can increase the risk of developing a fungal throat infection, called thrush;
  • Nausea, vomiting and fatigue - chemotherapy and radiotherapy can result in nausea, vomiting and fatigue. 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 - this may occur after a treatment session and can last a few days, and;
  • Temporary hair loss - some types of chemotherapy result in hair loss on the head and body. It will grow back after treatment has ended.

Advanced throat cancer

Advanced throat cancer can spread throughout the body via the bloodstream and lymphatic system (metastasise).

Lymphatic system

A network of vessels, lymph nodes, the spleen and other organs that transport lymph fluid between tissues and bloodstream.

Prognosis

The prognosis depends on the type and stage of cancer. For cancer of the laryngopharynx, the five-year survival rate is 65%, increasing to 72% for those who survive the first year and to 81% for those who survive five years. [1]

Statistics are not readily available in Australia for nasopharyngeal or oropharyngeal cancer, but your doctor, who specialises in cancer treatment (oncologist), will inform you of the prognosis. 

In general, cancers associated with HPV infection tend to have better survival rates.

It is important to remember survival rates are only an indication, and are based upon the averages of previously treated patients. It is not an absolute prognosis for an individual. It is often difficult to accurately predict an individual's cure or survival rate. Constant advances in treatment are continually improving these statistics. 

HPV

A virus with many subtypes that cause warts, including common warts of the hands and feet, and genital warts. Some strains of HPV cause cervical cancer.

1. Cancer survival and prevalence in Australia: period estimates from 1982 to 2010. Australian Government – Australian Institute of Health and Welfare. Accessed 22 September 2014 from

External link

Prevention

There is no way to prevent throat cancer, but you can reduce your risk by not smoking, minimising your alcohol consumption and eating a healthy diet high in fruit and vegetables.

1. Cancer survival and prevalence in Australia: period estimates from 1982 to 2010. Australian Government – Australian Institute of Health and Welfare. Accessed 22 September 2014 from

External link