Kidney cancer

How cancer develops

         

The kidneys

The kidneys are two bean-shaped organs found near the middle of your back, one on either side of your spine. The kidneys are part of your urinary system. They filter your blood to remove waste products from it and these are made into urine. Urine then drains into your bladder down tubes called ureters. You have two ureters – one from each kidney. Another tube, called the urethra, then carries urine from your bladder out of your body.

The kidneys also produce three important hormones (chemicals produced by your body).

  • Erythropoietin (EPO) helps your bone marrow to make red blood cells.
  • Renin controls your blood pressure.
  • Calcitriol (a form of vitamin D) helps your bowel to absorb calcium from your diet.

About kidney cancer

The organs and tissues of your body are made up of cells. Usually, cells grow and divide in an orderly and controlled way. However, if this process gets out of control, the cells carry on growing and dividing and develop into a lump called a tumour. Tumours are either non-cancerous (benign) or cancerous (malignant).

Cancerous tumours can grow through your kidney and spread to other parts of your body (through your bloodstream or lymphatic system) where they may grow and form secondary tumours. Your lymphatic system is made up of the tissues and organs, including the bone marrow, spleen, thymus and lymph nodes, that produce and store cells that fight infection and disease. The spread of cancer is called metastasis.

Kidney cancer isn’t infectious and it can’t be passed on to other people. Usually, only one of your kidneys is affected – it’s rare for cancer to develop in both of your kidneys.

In the UK, about 7,800 people are diagnosed with kidney cancer each year. It’s the eighth most common cancer and affects more men than women. More people get kidney cancer when they are over 75. It’s rare for people under 40 to get kidney cancer, but there is a rare type called Wilms’ tumour (also known as nephroblastoma) that affects very young children.

Types of kidney cancer

There are several types of kidney cancer. Renal cell cancer (RCC) is the most common type of kidney cancer in adults. More than eight in 10 people with kidney cancer in the UK have this type. In RCC, the cancerous cells are found in the lining of your tubules (the smallest tubes inside your kidneys that help filter the blood and make urine).

There are several different types of RCC, but all of these are treated in the same way. The main ones are:

  • clear cell
  • papillary (types 1 and 2)
  • chromophobe
  • oncocytic
  • collecting duct

Another type of kidney cancer is called transitional cell cancer (TCC), which affects part of your kidney called the renal pelvis. This type of kidney cancer is less common. About eight in 100 people with kidney cancer in the UK have TCC. This type of cancer can develop in your bladder, as it affects the lining of your whole urinary system.

Another type of kidney cancer, called Wilms' tumour, can affect children. This is different from kidney cancer in adults and is uncommon – about 70 children in the UK develop Wilms' tumour each year. It most often affects children under five.

This factsheet will focus on RCC.

Symptoms of kidney cancer

When kidney cancer first starts to develop, you won’t have any obvious symptoms. It’s sometimes picked up on ultrasound scans that are done for other reasons. When the cancer begins to grow, your symptoms can become more obvious.

Having blood in your urine is the most common symptom of kidney cancer. More often, blood in your urine is caused by an infection, an enlarged prostate (if you’re a man) or kidney stones. However, if you see blood in your urine, you should see your GP.

It’s possible that you might feel a lump or swelling in the area of your kidneys, although most kidney cancers are too small to feel.

Other symptoms of kidney cancer may include:

  • tiredness
  • loss of appetite
  • weight loss
  • a high temperature and heavy sweating
  • a pain in your side that won’t go away
  • a general feeling of being unwell

High blood pressure (hypertension) and anaemia (a condition in which your blood can't carry enough oxygen to meet the needs of your body) can also be signs of kidney cancer.

These symptoms aren't always caused by kidney cancer, but if you have them, see your GP.

Causes of kidney cancer

The causes of kidney cancer aren't fully understood at present. However, several things are known to increase your risk of developing kidney cancer, including the following.

  • Being overweight or obese. This can increase your risk of developing kidney cancer.
  • Smoking. If you smoke, your risk could be double that of a non-smoker – the longer you smoke for and the more cigarettes you smoke, the greater your risk.
  • Inherited risk. Although most kidney cancers aren’t inherited, sometimes two or more members of the same family develop kidney cancer. If you have a relative with kidney cancer, you may have an increased chance of developing it.
  • Inherited conditions. There are some rare conditions, such as von Hippel-Lindau disease, where an inherited faulty gene increases your risk of developing kidney cancer.
  • Kidney disease. Having kidney disease that needs to be treated with dialysis can increase your risk of developing kidney cysts and this can increase your risk of kidney cancer.
  • Hepatitis C infection. Some research has suggested that if you're infected with hepatitis C virus, you have almost double the risk of developing kidney cancer compared to those who aren't.
  • Treatment for cancer. If you have had previous treatment for testicular cancer or cervical cancer, your risk of developing kidney cancer is higher.
  • High blood pressure. Having high blood pressure may increase your risk.
  • Excessive use of over-the-counter painkillers, such as aspirin, paracetamol and ibuprofen, may increase your risk of developing kidney cancer.

Diagnosis of kidney cancer

Your GP will ask you about your symptoms and examine you. He or she may test a sample of your urine with a dipstick and may also take a blood sample for testing.

If you have blood in your urine, you may be referred to a haematuria clinic. All the tests needed to make a diagnosis can usually be done at the same time and you can go home the same day.

Your GP may refer you to an urologist (a doctor who specialises in conditions that affect the urinary system) for further tests, which may include the following.

  • Cystoscopy. This is a procedure used to look inside your bladder and urinary system, which may be done if you have blood in your urine. It doesn’t look at your kidneys, but it can check your bladder lining for signs of bleeding.
  • Ultrasound scan. This uses high-frequency sound waves to produce an image of your kidneys. The test is painless and will only take a few minutes. It can be used to look for changes in the shape of your kidneys, and can also measure the size and position of a tumour.
  • CT scan. This uses X-rays to make a three-dimensional image of your kidneys.
  • MRI scan. This uses magnets and radiowaves to produce two and three-dimensional images of the inside of your kidneys.
  • An image-guided biopsy. Your doctor will use an ultrasound or CT scanner to guide him or her to the area of your kidney where the biopsy (tissue sample) will be taken. The sample will then be sent to the laboratory to be examined under a microscope.

Treatment of kidney cancer

Your doctor will plan your treatment by taking into account several factors, including your age and general health, the type and size of the tumour, and whether it has spread.

Surgery

Surgery is the main treatment for kidney cancer. If all of the cancer can’t be removed by surgery, other treatments may be used.

Early stages of kidney cancer are most likely to be curable with surgery. Your surgeon will either remove your whole kidney (radical nephrectomy) or just the affected part of your kidney (partial nephrectomy). Sometimes it may be possible to have keyhole surgery. In this operation, your surgeon uses a laparoscope (a fine tube with a camera attached) to remove some or all of your kidney. He or she makes only small cuts in your abdomen (tummy) instead of one larger cut.

There are other surgical treatments available, which may be suitable if you have smaller kidney tumours or if you aren’t healthy enough to have conventional surgery.

  • Percutaneous radiofrequency ablation. This uses heat to destroy cancer cells. You will be given local anaesthesia. This completely blocks pain from the area over your kidney and you will stay awake during the procedure. Your surgeon will then place one or more needle-like electrodes through your skin into the centre of your tumour. An electrical current is then passed into your tumour. This heats the cancer cells and destroys them. You may need to have this treatment more than once.
  • Cryotherapy. This uses very cold temperatures to destroy cancer cells. You might be offered this treatment if you have a very small kidney tumour. It’s usually carried out under general anaesthesia. This means you will be asleep during the procedure. Your surgeon will place one or more probes into the centre of your tumour. Liquid nitrogen is then passed through the probes to freeze and destroy cancer cells.
  • High-intensity focused ultrasound. This type of treatment uses sound waves to produce high temperatures inside cancer cells to destroy them. It may be carried out under local or general anaesthesia. However, this treatment is newer than other treatments, so it’s not known exactly how effective it is.

Non-surgical treatments

Radiotherapy
Radiotherapy uses X-rays to destroy cancer cells, while doing as little harm as possible to normal cells. You’re most likely to be offered this treatment to shrink your cancer if it’s causing you pain or to treat cancer that has spread to other parts of your body, such as your bones or brain.

Chemotherapy
Chemotherapy uses anticancer medicines to destroy cancer cells. It works by disrupting the growth of cancer cells. Chemotherapy isn't often used to treat RCC, but you might be offered it in combination with another treatment.

Biological therapy
Biological therapy uses medicines based on substances produced by the body to kill cancer cells or stop them growing. You may be offered biological therapy if your kidney cancer has spread or if you’re at high risk of it coming back after having surgery to remove your tumour.

Prevention of kidney cancer

You may be able to reduce your risk of developing kidney cancer by making certain changes to your lifestyle, such as stopping smoking, losing excess weight and eating a healthy, balanced diet.

Help and support

Being diagnosed with cancer can be distressing for you and your family. An important part of cancer treatment is having support to deal with the emotional aspects as well as the physical symptoms. Specialist cancer doctors and nurses are experts in providing the support you need, and may also visit you at home. If you have more advanced cancer, further support is available to you in hospices or at home – this is called palliative care.

Is it true that taking over-the-counter painkillers causes kidney cancer?

Answer

There is a link between taking some over-the-counter painkillers and kidney cancer, but this link has only been found in people who take a lot of painkillers over a long period of time.

Explanation

Research into the use of painkillers and kidney cancer risk is still at an early stage. A painkiller called phenacetin was found to increase the risk of developing kidney cancer, but this medicine has now been banned in the UK and many other countries. Taking some over-the-counter painkillers, such as aspirin, paracetamol, ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDs), has been found to slightly increase your risk of developing kidney cancer.

However, this risk only applies to you if you take a lot of these painkillers over a long period of time. It’s unlikely that occasional use of painkillers or taking a low dose would be harmful – studies have only found a slight risk of developing kidney cancer with regular use of paracetamol.

If you’re taking painkillers regularly and are concerned that you may be at risk of getting kidney cancer, speak to your GP.

What is TNM staging for kidney cancer?

Answer

The TNM staging system is a way for doctors to assess your tumours and how far your cancer has spread. It’s used to assess many different types of cancer, including kidney cancer. The tests you have to diagnose your cancer will give your doctor some information about its stage. The staging system is important because the type of treatment you have is often decided according to the stage of your cancer.

Explanation

In the TNM system, the T stands for tumour, the N stands for nodes and the M stands for metastases (the spread of cancer).

In stage T1, your tumour is no bigger than 7cm across and is inside your kidney. In T2, it’s larger, but still inside your kidney. If your cancer is stage T3, it has spread to tissue surrounding your kidney and in T4, it has spread to another part of your body.

N0 means there is no cancer in any of your lymph nodes. In stage N1, the cancer has spread to one of your nearby lymph nodes only and in N2, to more than one. M1 means your cancer has spread (metastasised) and M0 means it hasn’t. Cancer that has spread is called advanced kidney cancer.

Your doctor will combine the T, N and M stages of your tumour to give it an overall stage.

  • Stage 1 – your cancer is less than 7cm across and is inside your kidney.
  • Stage 2 – your cancer is more than 7cm across, but is inside your kidney.
  • Stage 3 – your cancer has grown into your adrenal gland or one of your major veins. There is only one nearby lymph node containing cancer cells.
  • Stage 4 – your cancer has grown into surrounding tissue and there is more than one lymph node containing cancer cells, or your cancer has spread to another part of your body.

If you need more information or further explanation of the stage of your cancer, speak to your doctor.

What can I do to help prevent kidney cancer?

Answer

There are several changes you can make to your lifestyle to reduce your risk of developing kidney cancer. These include maintaining a healthy weight, exercising regularly, drinking alcohol in moderation and if you smoke, quitting.

Explanation

If you smoke, your risk of developing kidney cancer is double that of a person who doesn't smoke. The longer you smoke for and the more cigarettes you smoke, the more your risk increases. If you stop smoking, your risk of developing kidney cancer will most likely decrease. Quitting smoking also reduces your risk of getting other serious health conditions, such as lung cancer and heart disease. Your GP can give you support and advice about how to quit.

If you’re overweight or obese, you’re at a greater risk of getting kidney cancer, as well as a number of other cancers. Being overweight causes changes in your hormones (chemicals produced by your body), particularly if you’re a woman – this change in your body’s hormone balance may increase your risk of developing kidney cancer. If you're overweight, try to follow a healthy, balanced diet and take part in regular physical activity to lose excess weight. The recommended healthy level of physical activity is 150 minutes (two and a half hours) of moderate exercise (this means your breathing is faster, your heart rate is increased and you feel warmer) over a week. You can do this by carrying out 30 minutes on at least five days each week. You don’t have to go to the gym to get the health benefits of exercise. You can incorporate exercise into your daily routine – do something you enjoy like gardening, walking or dancing.

There is still some uncertainty over the role of diet in kidney cancer. Some studies have shown that eating a diet rich in fruit and vegetables can reduce your risk, and that eating large amounts of well cooked (well done) meat may increase your risk, but there is not enough evidence to say that this is definitely the case. However, eating a healthy, balanced diet, rich in fruit and vegetables, can lower your risk of many other diseases and generally keep you healthy.

The risk of developing kidney cancer is slightly lower in people who drink alcohol in moderation compared to people who don’t. However, drinking large amounts of alcohol increases your risk of developing several other cancers. It can also cause other medical conditions, such as having high blood pressure (hypertension), which may increase your risk of kidney cancer. Try to have at least two alcohol-free days a week and stick to the recommended daily drinking guidelines (three to four units for men and two to three units for women – a pint of strong beer or a large glass of wine is three units).