Cancer of the thyroid gland

The thyroid gland is located at the base of your neck and is responsible for the production of hormones. These hormones regulate the speed at which food is converted into energy within the body. This energy then drives the various processes within the body.

This process is known as the metabolism. Your metabolic rate is the speed at which this process occurs which is directed by hormones released by the thyroid gland, e.g. thyroxine.

We all have an individual metabolic rate with some people having a faster metabolism than others. But the thyroid gland can ‘malfunction’resulting in too many hormones - known as an overactive thyroid, or too little hormones –known as an underactive thyroid.

The thyroid gland also controls the amount of calcium within your body.

The thyroid gland is comprised of two halves, joined by a bridge. The bridge is called the ‘isthmus’ and the two halves are called ‘lobes’.

It is important to understand this as cancer usually develops in one or the other lobe. But if cancer of the thyroid occurs as a result of family history then it tends to develop in both lobes.

Cancer of the thyroid is one of the rarest forms of cancer in the UK.

Causes of cancer of the thyroid

It is difficult to determine an exact cause of this cancer but there are several risk factors which include:

• Thyroid diseases such as goitre (enlarged thyroid gland) and nodules (swellings on the thyroid).
• Family history
• Radiotherapy treatment or exposure to radiation
• Low iodine levels
• Acromegaly (over production of growth hormone)

There are some additional risk factors which possibly cause thyroid cancer although this is yet to be proven. These include:

• Smoking
• People who have suffered from a previous form of cancer
• Specifically female factors, e.g. menopause, pregnancy etc
• Excess alcohol consumption
• A diet high in sugar or high fat foods

Symptoms of cancer of the thyroid

These include a sore throat, a lump in your neck, hoarse voice and a difficulty in swallowing.

These symptoms can be indicative of other conditions such as throat infections so do not assume that a sore throat or hoarseness means that you have thyroid cancer. You may have a bacterial or viral throat infection instead.

However, if you do have a lump in your neck then get this checked by your GP especially if you have noticed an increase in size.

More than one type of thyroid cancer

There are 5 types of thyroid cancer which are:

• Papillary
• Follicular
• Anaplastic
• Medullary
• Lymphoma

Papillary

Papillary is the most common form of thyroid cancer which occurs in young people and women. This is a slow growing form of cancer which can spread to the lymph nodes.

Follicular

Follicular is often found in young and middle aged adults. This cancer often spreads to other areas of the body for example the bones.

Anaplastic

Anaplastic develops in older people especially those over 60 years old. It occurs in women more than men and is the fastest growing form of thyroid cancer.

Medullary

Medullary is a very rare form of cancer which usually develops as a result of a genetic defect. This cancer may spread to the lungs or bones.

Lymphoma

Lymphoma or ‘Non-Hodgkin’s Lymphoma’ is another very rare form of thyroid cancer.

Diagnosing cancer of the thyroid

As these symptoms may indicate a less serious condition, for example a bacterial throat infection it can be difficult to determine if this is the case or if you have signs of possible thyroid cancer.

But if you have a particular symptom such as noisy breathing (known as ‘stridor’), lumps in your throat or a single lump which keeps increasing in size then you will be referred to a specialist.

Your GP will examine you, ask you about your medical history and any inherited diseases or family history. He/she can conduct a blood test with the aim of checking your thyroid levels although this may be done at the hospital.

He or she will refer you to a specialist if you exhibit any of the symptoms mentioned above and:

• If you are aged 65 and over or are a child (before adolescence).
• Your voice has changed or become hoarseness for which there is no obvious reason.
• The lump in your thyroid gland keeps on growing
• There is a history of thyroid cancer within your family
• You have undergone radiotherapy to your neck as a part of a previous treatment.

These all require further investigation.

Once you have been referred to a specialist you will undergo a battery of tests at the hospital. These will include X-rays, an ultrasound scan, a biopsy and blood tests. The blood tests will include checking your thyroid levels if this has not been done at your GP’s surgery.

The ultrasound scan involves using sound waves to obtain a series of images of your thyroid and neck. This will show an internal view of these and whether any lumps you may have are solid or filled with liquid. A solid lump is often an indication of cancer although a biopsy will be needed to confirm this.

The biopsy entails the insertion of a fine needle into the lump in your neck from which a sample of cells and fluid is drawn off. This is then sent to a laboratory for analysis under a microscope. The aim is to see if this contains cancerous cells or not.

If a needle biopsy is not undertaken then a surgical biopsy will be performed instead. This involves the surgical removal of a small section of tissue from the thyroid which is also sent to analysis.

Are there any more tests?

Your specialist will send you for further tests if the initial tests show that you have cancer of the thyroid. These additional procedures are designed to ascertain the extent or ‘stage’of the cancer and how far it has spread.

They will also include checking your lymph nodes to see if these are enlarged which may indicate that the cancer has spread to these glands.

These tests include:

• Thyroid scan
• PET-CT scan
• CT scan
• MRI scan

(Source: Cancer Research UK: thyroid cancer)

Thyroid scan

A thyroid scan entails the use of a ‘gamma camera’ and radioactive iodine. This iodine is injected into your arm followed by the gamma camera being placed over your neck. This iodine shows up in your thyroid cells but cancerous cells do not show any traces of iodine as quickly as these.

PET-CT scan

A PET-CT scan is able to show highly detailed images of the tissues within the body. They enable a cross section of a part of the body, e.g. the neck to be seen and are a highly effective diagnostic tool.

However, PET-CT scanning equipment is expensive and as a result of this only a certain number of hospitals in the UK have this type of scanner.

CT/MRI scan

A CT scan or an MRI scan is equally useful at detecting signs of cancer within the thyroid. An MRI scan in particular uses magnetism to produce a cross section of images of an area of the body which is very accurate. It can give better images than a CT scan although this depends upon which part of the body it is used for.

What happens after this?

Once you have had these tests you then have to wait for a short period of time –around a week or so –until your results are ready.

We realise that this is a stressful and nerve wracking time which can be eased by talking to someone close to you. It may help to talk to a close friend or member of your family or if you prefer, a counsellor or someone at a cancer support group.

The waiting is often the worst part but having someone with you can help.

Treatment for cancer of the thyroid

Once your results are back the next step is to decide upon a suitable course of treatment. This very much depends upon the spread (or extent) of your cancer, your age, lifestyle and general health.

This also includes the type of thyroid cancer you have. Some types of thyroid cancer are easier to treat than others.

What will happen is that your treatment will be placed in the care of a multi-disciplinary team which consists of a range of healthcare professionals. This will include your cancer specialist, surgeon or surgeons, speech therapist, cancer nurse etc. The team is concerned with your treatment and your wellbeing. They will discuss the results with you and invite you to ask any questions before devising a treatment plan.

Treatment options include:

• Surgery
• Chemotherapy
• Radiotherapy
• Thyroid hormones (occasionally)

Surgery is performed to remove some or all of the thyroid gland. This may also include the lymph glands in the surrounding area. If surgery does not successfully remove all of the cancer it can be combined with radiotherapy to help control it.

Chemotherapy and radiotherapy are used to kill cancer cells or to shrink the size of a tumour. This is useful as a way of preventing the further spread of the cancer.

Chemotherapy uses a blend of drugs known as ‘cytotoxic drugs’which help to destroy cancer cells. However, this is not usually the preferred course of treatment with surgery and radiotherapy being used instead.

These two forms of treatment appear to be more effective although chemotherapy (or ‘chemo’for short) is used to treat an advanced stage of thyroid cancer. It is also used in cases in which thyroid cancer has re-occurred.

If your entire thyroid is removed – in a procedure known as a thyroidectomy, then you will have to take thyroid hormones (tablets) for the rest of your life.

These are designed to replace the hormones lost as a result of surgery.

One of the biggest factors with any of this is coping with cancer. This is an extremely stressful and anxious time which raises a number of issues related to physical and emotional changes, financial matters and living with cancer.

The Cancer Research UK website has useful information about coping with cancer.