Thyroid cancer

There are four main types of thyroid cancer. These are listed below. The papillary and follicular types are sometimes grouped together and are called differentiated thyroid cancer.

1. Papillary thyroid cancer is the most common type of thyroid cancer. It's usually slow growing and is most common in women and in younger people.
2. Follicular thyroid cancer is less common than papillary thyroid cancer and usually affects slightly older people. It can spread to other parts of the body such as the lung or bones.
3. Anaplastic thyroid cancer is also rare. It tends to grow more quickly than other types of thyroid cancer and can be more difficult to treat. About three in 20 people with thyroid cancer have this type. It's more common in older people and women.
4. Medullary thyroid cancer is rare and affects about one in 20 people with thyroid cancer. For around one in every four people with medullary thyroid cancer it's a hereditary condition, which means it's passed down through family generations. It can spread to other parts of body, such as the lungs and bones.

It's also possible to get another type of cancer, called lymphoma in your thyroid gland, although this is rare.

The causes of thyroid cancer aren't fully understood at present. There are, however, certain factors that make developing thyroid cancer more likely. The following factors may increase your risk of the disease.

• History of non-cancerous (benign) thyroid disease, such as an enlarged thyroid or inflammation of the thyroid.
• Radiotherapy to the neck area, particularly if this was done at a young age.
• Not enough iodine in the diet.
• An inherited bowel condition called familial adenomatous polyposis (FAP).
• Family history of medullary thyroid cancer.

Lumps in the thyroid gland are quite common. For example, nine out of 10 women over the age of 70 will have a thyroid lump. If you have thyroid cancer, you may have some of the following symptoms:

• a painless lump in your neck, which gradually gets bigger
• difficulty swallowing
• breathing problems
• a hoarse voice

Medullary thyroid cancer can cause other symptoms including diarrhoea and redness of the face.

These symptoms can be caused by problems other than thyroid cancer. If you have any of these symptoms, visit your doctor for advice.

Your doctor will ask you about your symptoms and will examine you. He or she may also ask you about your medical history and arrange initial blood tests. If your doctor thinks you may have a thyroid tumour then you will be referred to a doctor who specialises in thyroid cancer for further tests. The main tests may include the following.

• A blood sample to check, for example, the thyroid hormone levels in your blood.
• An ultrasound scan of your neck which uses sound waves to produce an image of the thyroid.
• A biopsy of a lump in your thyroid. A biopsy is a small sample of tissue. Your doctor may use an ultrasound scan to guide a needle to the thyroid lump to take a biopsy. Alternatively, a small operation may be performed under general or local anaesthesia, where a small cut is made in your neck and a biopsy is taken from the thyroid gland. This will be sent to a laboratory for testing to find out if the cells are benign (not cancerous) or cancerous.

The results of your tests will decide the treatment you need. If you have cancer, you may need to have other tests to assess if the cancer has spread. The process of finding out the stage of a cancer is called staging.