The thyroid gland and the parathyroid glands are part of the endocrine system. Although they are close to each other and have similar names, they have very different functions.
The parathyroid glands
There are four parathyroid glands, which are attached to the thyroid gland, in the front of the neck.
The parathyroid glands are small, but their function is very important: they maintain the correct levels of calcium in the body. Calcium plays an essential role in controlling muscle and nerve function.
Position of the parathyroid glands
Parathyroid tumours can be non-cancerous (benign) or cancerous (malignant). Most tumours of the parathyroid gland are benign. This information discusses the malignant endocrine tumours of the parathyroid glands. Cancer of the parathyroid gland is extremely rare.
A tumour of the parathyroid gland may cause the overproduction of the hormone that controls the level of calcium in the body. The hormone is called parathyroid hormone (PTH), or parathormone.
Causes of parathyroid gland cancer
The exact cause of parathyroid tumours is not fully understood, but we do know that the risk of developing it increases in people affected by a condition known as multiple endocrine neoplasia 1 (MEN1). This is a rare condition that is caused by a faulty gene; it can be passed on from one generation to another (inherited).
Cancer of the parathyroid glands has also been linked to exposure to radiation.
Signs and symptoms
Some people with a parathyroid tumour may feel a lump or swelling in their neck, but this is not common.
If parathyroid hormone is being overproduced, it may cause some of the following symptoms:
high levels of calcium in the blood (hypercalcaemia)
Some people may only have one or two of these symptoms. These symptoms may also be caused by other conditions not related to parathyroid tumours.
Before a diagnosis can be made, your doctor will ask you about your past medical conditions, including any symptoms that you have.
A number of tests will be done. These may include any of the following:
Blood and urine tests Samples of blood and urine are taken to look for the presence of certain hormones. A sample of urine may be collected over a 24 hour period. Sometimes it is necessary to fast (not eat) overnight before having certain blood tests.
Parathyroid scan This scan can identify the size and position of the parathyroid glands, and how well they are working. A slightly radioactive substance is injected into a vein in your arm. The scan shows how much of the substance is taken up by the parathyroid glands, and identifies any abnormal areas.
X-rays and scans A combination of x-rays and scans will be taken to find where the tumour is, and if it has spread.
Ultrasound scan Sound waves are used to make up a picture of the neck area. Once you are lying comfortably on your back, a gel is spread over your neck. A small device like a microphone, which produces sound waves, is then passed over the area.
CT (computerised tomography) scan This is a series of x-rays, which builds up a three‑dimensional picture of the inside of the body. The scan is painless. It takes about 30 minutes.
MRI (magnetic resonance imaging) scan This uses magnetism instead of x-rays to form a series of cross-sectional pictures of the inside of the body. During the scan you will be asked to lie very still on a couch inside a metal cylinder. The test can take up to an hour and is completely painless. If you don't like enclosed spaces, you may find the machine claustrophobic. The machine is also quite noisy, but you will be given earplugs or headphones to wear.
PET (Positron emission tomography) scan This is a new type of scan and is occasionally used for this type of tumour. A PET scan uses low-dose radioactive sugar to measure the activity of cells in different parts of the body. Areas of tumour are usually more active than surrounding tissue, and show up on the scan. If you need a PET scan, you might have to travel to a specialist centre to get one.
Biopsy A small sample of cells is taken from the tumour to be examined under a microscope. A local or general anaesthetic may be given.
If the tumour is contained in one area (localised), or if there has been only limited spread, surgery is usually the first choice of treatment. If it is possible to remove the tumour completely, no other treatment may be necessary.
Surgery usually involves removing all of the parathyroid gland and part, or all, of the nearest half of the thyroid gland, and some surrounding tissue. After the operation, the calcium levels in the body can go up and down. Your doctors will monitor your calcium level by taking regular blood tests.
Usually, this type of surgery is done under a general anaesthetic and requires a short stay in hospital. Sometimes it is possible to remove the affected parathyroid gland using keyhole surgery, under a local anaesthetic. However, the effectiveness of this technique is still being investigated in research trials.
This is the use of high-energy rays. Radiotherapy can be given after surgery, with the aim of reducing the risk of the cancer coming back. It may also be given If your cancer comes back some time after the initial surgery, or if it has spread to another part of the body.
This uses anti-cancer (cytotoxic) drugs to destroy cancer cells. Chemotherapy is occasionally used for parathyroid cancer that has come back after initial treatment, or has spread to other parts of the body.
Medicines known as bisphosphonates can be given to reduce high levels of calcium in the blood (hypercalcaemia).
These are medicines that are used to control some of the symptoms associated with an overproduction of parathyroid hormone (PTH) and hypercalcaemia.
Research into treatments for parathyroid cancer is ongoing and advances are being made. Cancer doctors use clinical trials to assess new treatments. Before any trial is allowed to take place it must have been approved by an ethics committee, which will have checked whether the trial is in the interest of patients.
You may be asked to take part in a clinical trial. Your doctor must discuss the treatment with you so that you have a full understanding of the trial and what it involves. You may decide not to take part, or to withdraw from a trial, at any stage. You will then receive the best standard treatment available.
You may have many different emotions including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their illness.
Each individual has their own way of coping with difficult situations; some people find it helpful to talk to friends or family, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to cope; but help is there if you need it. You may wish to contact our cancer support service for information about counselling in your area.