Tumours of the adrenal glands

The endocrine system

The endocrine system is a network of endocrine glands and nerves throughout the body. Endocrine glands produce and release hormones that circulate around the body in the blood. Hormones keep an even balance of chemicals and fluid within the body, and help us respond to changes in the environment. The endocrine system is made up of several glands, including the thyroid gland, the parathyroid glands, and the pituitary gland.

Endocrine tumours

Endocrine tumours are a rare group of tumours that start in the cells of the endocrine system. Most endocrine tumours are non-cancerous (benign), but some are cancerous (malignant).

Endocrine tumours are classified according to:

• the particular endocrine glands that are involved
• the type of cell from which the cancer developed
• the part of the body that is affected.

The adrenal glands

There are two adrenal glands. One sits on the top of each kidney. The adrenal glands produce a number of vital hormones essential for survival.

There are two parts of the adrenal glands. The inner part is known as the medulla, and the outer part of the gland is called the cortex.

Position of the adrenal glands

When a tumour develops in the adrenal glands, it often causes too much of a particular hormone to be produced. The type of hormone overproduced depends on the part of the adrenal gland that is affected by the tumour.

Some endocrine tumours may not cause an overproduction of hormones and do not cause any obvious symptoms. These are known as non-functioning tumours.

The adrenal cortex

The adrenal cortex produces different types of hormones. These are known collectively as steroids. They regulate different mechanisms within the body. The different types of steroids are:

• Glucocorticoids regulate the way that the body uses carbohydrate, protein, and fat. They also affect the levels of glucose in the blood.
• Mineralocorticoids control the balance of sodium (salt) and water in the body, which maintains the amount of blood in the heart and circulatory system, and regulates blood pressure.
• Sex hormones Although the male hormones (androgens) and female hormones (oestrogen and progesterone) are mainly produced by the testes and ovaries respectively, the adrenal cortex also produces small amounts of androgens in both men and women.

The adrenal medulla

The adrenal medulla produces the hormones adrenaline (epinephrine) and nor-adrenaline (norepinephrine). These hormones make the heart beat faster and cause sweating, an increased blood supply to vital organs, slowing of digestion and dilatation of the pupils of the eye. These effects are important in helping the body to react to emergency situations. Adrenaline and nor-adrenaline are sometimes called the hormones of 'fight or flight'.

Types of adrenal tumours

Tumours of the adrenal gland can develop in either the cortex or the medulla.

Benign tumours of the cortex are called adrenal cortical adenomas. Malignant tumours are called adrenal cortical carcinomas.

The most common type of tumour in the medulla is called a phaeochromocytomafee-oh-cromo-sigh-toma). A small number of phaeochromocytomas start outside the medulla part of the adrenal gland and are known as extra‑adrenal phaeochromocytomas. (pronounced

Usually, only one adrenal gland is affected. Rarely, tumours may occur in both adrenal glands; these are known as bilateral adrenal tumours.

Causes of adrenal cancer

As with many other forms of cancer, the exact causes of adrenal cancer are usually unknown. However, the risk of developing an adrenal tumour is increased in people who have Multiple Endocrine Neoplasia (MEN1 and 2).

MEN1 and MEN2 are very rare conditions caused by an inherited faulty gene. MEN1 is associated with adrenal adenomas, and MEN2 is associated with phaeochromocytoma (which can be malignant). People who have relatives with MEN can ask their GP to refer them to a family cancer clinic for advice and for genetic testing.

Signs and symptoms

Functioning tumours may cause symptoms because they produce excess amounts of particular hormones. The symptoms will depend on the hormone that is being overproduced.

When a tumour does not produce high levels of hormones (is non-functioning), it can start to cause symptoms after a period of time because of its position or size. Pressure on surrounding organs may cause symptoms such as pain.

Carcinoma of the adrenal cortex

About 2 out of 3 adrenal cortical carcinomas cause symptoms by producing high levels of one or other of the adrenal cortex hormones. The particular hormone being overproduced will determine the symptoms, with some tumours producing more than one class of steroid.

Glucocorticoid This can lead to weight gain, particularly in the trunk area, while there is usually some muscle wasting of the limbs, making them appear thinner. There can also be an accumulation of fat at the base of the neck, which can lead to a 'buffalo hump' appearance. There can also be a swelling of the cheeks and face, giving a 'moon face' appearance.

Some people have mild diabetes, which can cause an increase in thirst and a need to pass urine more frequently. Other symptoms include high blood pressure (hypertension), weakened bones (osteoporosis), depression, and abnormal hair growth; fine, downy hair grows on the face, arms, and upper back. These symptoms, combined, are often called Cushing's syndrome.

Mineralocorticoids This can lead to an increase in blood pressure, muscle cramps, thirst, and excessive passing of urine. However, there are many other causes of raised blood pressure which are much more common than adrenal cortical cancers.

Sex hormones In women, this can lead to the development of male features such as a deepening of the voice and development of baldness. Periods may also be disturbed. In men, excess production of sex hormones may cause a loss of libido, impotence, and sometimes some swelling and enlargement of the breasts.

Tumours of the adrenal medulla

Phaeochromocytoma is the most common type of adrenal medulla tumour. Symptoms include:

• sudden attacks of panic and anxiety
• headaches
• pallor or flushing
• sweating
• palpitations (a racing heartbeat)
• hypertension (high blood pressure)
• irritability and mood changes
• weight loss.

Most phaeochromocytomas are benign, but they can be malignant. If you notice any of the above symptoms, contact your GP, but remember that these symptoms can also be caused by other conditions.

Diagnosis and tests

Tumours of the adrenal gland can be very difficult to diagnose. Usually, you begin by seeing your GP who will examine you and refer you to a hospital specialist.

The hospital specialist will organise any tests that may be necessary, and can give you expert advice and treatment. The doctor will take your full medical history, carry out a physical examination, and take blood samples to check your general health. The following tests may be carried out:

Blood and urine tests Several samples of blood and urine are taken to look for the levels of certain hormones. Samples of urine may be collected over a 24 hour period. Sometimes it is necessary to fast overnight before having certain blood tests taken. These tests may be repeated to monitor any consistent changes in hormone levels.

X-rays and scans A combination of x-rays and scans will be taken to locate the tumour and find out if it has spread.

Abdominal ultrasound Sound waves are used to make up a picture of the abdomen and surrounding organs. It is done in the hospital scanning department. You will be asked not to eat, and to drink clear fluids only (nothing fizzy or milky) for 4–6 hours before the scan. Once you are lying comfortably on your back, a gel is spread onto your abdomen. A small device, like a microphone, is then rubbed over the area. The sound waves are converted into a picture using a computer. The test is completely painless and takes about 15-20 minutes.

CT (computerised tomography) scan A CT scan takes a series of x-rays to build up a three-dimensional picture of the inside of the body. The scan is painless but takes about 30 minutes. It may be used to find where the cancer started (primary tumour) or to check for any spread of the disease (metastases).

MRI (magnetic resonance imaging) scan This scan 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 the 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.

123MIBG scan A drug called 123MIBG (Meta-iodobenzylguanidine) may be used to show up the site of a phaeochromocytoma. 123MIBG is mildly radioactive iodine that is taken up by adrenal cells. The scan takes place over two consecutive days in the nuclear medicine department. On the first day, you will go to the department twice. In the morning you will be given an injection in the arm. You are then free to stay in, or leave, the hospital. You will go back to the department in the afternoon to have a scan with a gamma camera, lasting for about an hour. The following morning you will have further pictures taken for about one and a quarter hours. At this point you may be given a further injection.

Biopsy A small sample of cells is taken from the tumour to be examined under a microscope. The biopsy may be carried out under a local or general anaesthetic.

Angiography An angiogram is a technique used to assess the flow of blood through the blood vessels of the adrenal glands. An injection is given into a vein in the arm, and a scan of the adrenal glands is then carried out.

Treatment

Treatment depends on a number of factors, such as the type and size of the tumour, and whether or not it has spread, and will therefore vary from person to person.

Surgery

If the tumour is contained in one area, 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.

The type of operation depends on the size and exact position of the cancer. Sometimes, the affected adrenal gland and kidney may need to be removed.

If the tumour has spread to other parts of the body, surgery may still be possible to remove the part of the tumour that is producing too many hormones. This is often referred to as tumour debulking.

If the tumour is causing a blockage, for example, in the bowel, surgery may be helpful to relieve the blockage.

Non-surgical treatments

• Drugs to lower blood pressure These are known as anti-hypertensive medicines.

• Steroids Sometimes, steroids may be given as tablets or by injection into a vein to reduce the size of an adrenal tumour, or to help to control symptoms that the tumour may be causing.

• Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. Chemotherapy may sometimes be used to treat adrenal tumours that have spread. It aims to shrink the tumour and reduce the amount of hormones it is producing.

• Radiotherapy uses high-energy rays to destroy cancer cells. Sometimes it will be given following an operation. The aim is to destroy any remaining cancer cells. Radiotherapy may also be given to treat symptoms, such as pain.

• Radionuclide therapy Some types of tumour may take up large amounts of particular chemicals, for example, MIBG. To treat these tumours, the chemical can be attached to a dose of a radioactive substance. As the cancer takes up the chemical, it also takes in the radioactivity. To test whether or not the tumour takes up large quantities of these chemicals, a scan will first be done using a tiny amount of radioactivity. If the tumour takes up the radioactivity, the treatment will be given using a higher dose of the radioactive substance. To have this treatment, you may need to be looked after in a room by yourself for a few days, so that other people are not exposed unnecessarily to the radioactivity.

Clinical trials

Research into treatments for adrenal tumours is ongoing and advances are being made. Cancer doctors use clinical trials to assess new treatments.

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.

Your feelings

Having a cancer diagnosis can be extremely frightening. You may experience many different emotions, including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process that many people go through in trying to come to terms with their condition.

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.

References

This section has been compiled using information from a number of reliable sources including:

• Oxford Textbook of Oncology (2nd edition). Eds Souhami et al. Oxford University Press, 2002.
• The Textbook of Uncommon Cancers (2nd edition). Eds Raghavan et al. Wiley, 1999.
• Endocrine Tumours. Eds Clark et al. Ontario, B C Decker Inc. 2003.

For further references, please see the general bibliography.

Via: http://www.cancerbackup.org.uk