The kidneys

Where the kidneys are?
The kidneys are two bean-shaped organs about the same size as a fist. They are located near the middle of the back, one on either side of the spine.

The kidneys are part of the body system called the urinary system. This system filters waste products out of the blood and makes urine. It is made up of the
• Kidneys
• Ureters
• Bladder
• Prostate (in men)
• Urethra

What the kidneys do?
The kidneys filter the blood. As the blood passes through the kidneys, waste products and unneeded water are collected and turned into urine.
The urine is gathered in an area called the renal pelvis at the centre of each kidney. From here it drains into the bladder down a tube called the ureter. There are 2 ureters - one from each kidney. Another tube called the urethra carries the urine from the bladder out of the body.

Inside the kidney, the blood is filtered through very small networks of tubes called nephrons. Each kidney has about 1 million nephrons. Inside the nephrons, waste products in the blood move across from the bloodstream (the capillaries) into the urine-carrying tubes inside the nephron. These tubes are called tubules. As the blood passes through the blood vessels of the nephron, all unwanted waste is taken away. Any chemicals needed by the body are kept or returned to the bloodstream by the nephrons. In this way, the kidneys help to regulate the levels of chemicals in the blood such as sodium and potassium, and keep the body healthy.
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Hormones from the kidneys:
As well as filtering waste products, the kidneys produce three important hormones
• Erythropoietin (EPO) tells the bone marrow to make red blood cells
• Renin regulates blood pressure
• Calcitriol (a form of Vitamin D) helps the intestine to absorb calcium from the diet, and so helps to keep the bones healthy
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The kidneys’ blood supply
The kidneys have a very rich blood supply. The blood needs to pass through in large quantities so that it can be filtered well, and all the waste products can be removed. The main blood supply carrying blood to each kidney is called the renal artery.
There are also large blood vessels carrying the cleaned blood away from each kidney. These are called the renal veins.
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The adrenal glands
Above each kidney, there is a small gland called the adrenal gland (‘ad renal’ means next to the kidney). The adrenal glands make hormones. They make
• A natural steroid hormone called cortisol
• A hormone that helps to regulate the body’s water balance called aldosterone
• Adrenaline
• Another adrenaline-like hormone called noradrenaline
If you have a kidney removed, you may have the adrenal gland above it removed too. This depends on where in your kidney the cancer is. If there is any chance that cancer cells could be left behind with your adrenal gland, then your surgeon will remove it.
The adrenal hormones are vital for life. You will be perfectly well with only one adrenal gland. Your other one will make all the hormones you need. If you have both kidneys and adrenal glands removed, you will have to take hormone tablets every day.
Risks and causes of kidney cancer


How common kidney cancer is
Kidney cancer is the 11th most common cancer diagnosed in the UK, with over 7,800 people diagnosed each year. Nearly 2 out 3 people diagnosed (62%) are over 65 years old. Kidney cancer is rare in people under 50. It affects many more men than women. This could be because in the past more men smoked cigarettes. Smoking increases your risk of getting kidney cancer.



Obesity
Obesity increases the risk of getting kidney cancer, particularly clear cell cancer. 'Obese' means that your body mass index is over 30. Or more roughly, that your weight is at least 25% higher than the top of the range for your height. Body mass index (BMI) is worked out by comparing your height and weight. Being overweight causes changes in hormones in the body, particularly for women. It could be this change in the body’s hormone balance that increases the risk of kidney cancer.


Smoking
If you smoke then your risk of getting kidney cancer could be double that of a non-smoker. The longer you continue to smoke and the higher the number of cigarettes you smoke, the higher the risk becomes. But if you stop smoking then your risk of getting kidney cancer will probably fall.


Kidney disease
People with kidney failure have to have their blood filtered by machine about twice a week. This is called dialysis. People having long term kidney dialysis have an increased risk of developing kidney cysts and this increases the risk of kidney cancer. The longer you are on dialysis, the greater your risk of kidney cancer. But this is probably because you needed dialysis due to kidney disease. The dialysis itself is not directly related to the cancer risk.


Faulty genes and inherited conditions
A small number of people inherit a tendency to develop kidney cancer. This is called hereditary or familial kidney cancer. The increased risk of cancer is related to an inherited faulty gene. Changes in the DNA that makes up the gene make it behave in an abnormal way and this can increase your risk of cancer. Scientists are finding out which genes carry these mistakes in the DNA. In the future this could help doctors predict who is at risk of getting hereditary kidney cancer.
People with kidney cancer who have these genetic conditions often have cancer in both kidneys (bilateral kidney cancer). They may also have several tumours in each kidney. They often develop the cancer at a younger age than people with non-inherited cancers..
The inherited conditions that greatly increase the risk of kidney cancer include
• Von Hippel-Lindau (VHL) syndrome
• Tuberous sclerosis
• Birt-Hogg-Dube syndrome
• Hereditary non vHL clear cell and papillary renal cell cancer
Von Hippel-Lindau (VHL) syndrome
Von Hippel-Lindau syndrome is an inherited cancer syndrome. The VHL gene runs through affected families. People who carry the gene have an increased risk of developing several quite rare cancers in the brain, spine, pancreas, eyes and inner ear. About 40% of people with vHL get kidney cancer.
Tuberous sclerosis
Tuberous sclerosis is another condition caused by a faulty gene. About 1 in 3 cases are inherited. But the other 2 out of 3 occur because the gene has mutated in those people for the first time. It can cause skin, brain and heart problems, as well as kidney disease. People with TS have an increased risk of kidney cysts and kidney cancer.
Birt-Hogg-Dube syndrome
Birt-Hogg-Dube syndrome is another inherited condition. It causes many benign tumours to develop in the hair follicles of the skin. These usually develop on the face, neck and trunk. People that carry this gene are at increased risk of kidney cancer.
Hereditary clear cell and papillary renal cell cancer
Hereditary clear cell kidney cancer and hereditary papillary kidney cancers are both caused by inherited faulty genes. They are dominant genetic conditions. This means that you only have to inherit the faulty gene from one parent. Even so, they are both very rare.


Chemicals at work
Sometimes, hazardous substances in the workplace can increase the risk of kidney cancer. There is evidence that working with coke ovens or blast furnaces in the iron or steel industries increases kidney cancer risk.
Asbestos might also increase the risk of kidney cancer. Asbestos can cause other types of cancer in the lung and mesothelium. The mesothelium is a sheet of tissue that surrounds and supports some body organs. People in a variety of occupations were exposed to asbestos in the past, including builders, car mechanics and shipyard workers.
Exposure to cadmium (a type of metal) and organic solvents, particularly trichloroethylene, may also be risk factors for kidney cancer. The risk if you work with cadmium is known to be greater if you also smoke.
Other occupations that may increase the risk of kidney cancer include dry cleaning and the petrochemical industry.


High blood pressure
Some research studies have found a link between high blood pressure or high blood pressure medicines and kidney cancer. It is more likely that high blood pressure is the link, rather than the medications. High blood pressure is a known risk factor for kidney disease in general.


Mild painkillers
Some mild painkilling drugs have been linked to increased kidney cancer risk. One drug that could definitely increase the risk was phenacetin, but this has been taken off the market in the UK. Other painkillers, such as aspirin, paracetamol, and a group of drugs known as 'non steroidal anti inflammatory drugs' (NSAIDs) may increase the risk of kidney cancer slightly. NSAIDs include ibuprofen (Nurofen). Research into painkillers and kidney cancer risk is at a relatively early stage. It is unlikely that occasional use or low dose use would be harmful. For example, some studies have only found a slight link with regular use of paracetamol.


Diet
Apart from obesity, we aren't sure what part diet plays in kidney cancer. Eating large amounts of well cooked meat or having a high fat intake may increase the risk. People who eat enough fruit and vegetables may lower their risk of kidney cancer. At this point, there isn't enough evidence to say for sure. But following these sort of dietary guidelines can lower your risk of other cancers, as well as heart disease. So you certainly won't be doing yourself any harm if you improve your diet. The risk of kidney cancer is slightly lower in people who drink alcohol compared to non-drinkers. However, alcohol increases the risk of several other cancers.
Symptoms of kidney cancer

Blood in the urine
This is the most common symptom of kidney cancer. Your doctor may call this haematuria. About half of those diagnosed with kidney cancer will have this symptom when they first go to the doctor.
The blood does not have to be there all the time. It can come and go. Sometimes, the blood cannot be seen by the naked eye but can be picked up by a simple urine test. If you ever see blood in your urine, you should go to the doctor.
Remember - most people who go to the doctor with blood in their urine do not have kidney cancer. In the majority of cases, blood in the urine is caused by an infection, enlargement of the prostate, or kidney stones. Even so, a doctor should always investigate blood in the urine. As the bleeding can come and go, both the doctor and the patient may get the impression that the problem has gone away. This can mean that an early, treatable cancer in the kidney or bladder is allowed to grow to the stage where it may not be so easy to treat.


A lump or mass in the area of the kidney
If you feel a lump or swelling in the area of your kidneys, you should go straight to your doctor. Most kidney cancers are too small for you or a doctor to feel. But it is possible for the kidneys to be scanned to check for cancer.

Other more vague symptoms
Some people can have other symptoms, which can be vague. These are
• Tiredness
• Loss of appetite
• Weight loss
• A high temperature and very heavy sweating
• A pain in the side that won’t go away
• A general feeling of poor health
A high temperature and sweats can be caused by an infection, and your doctor may want to rule this out first.
High blood pressure and having fewer red blood cells than normal (anaemia) can also be symptoms of kidney cancer. These symptoms are related to the hormones that the kidneys produce.
Types of kidney cancer



Renal cell cancer
Renal cell cancer is the most common type of kidney cancer in adults. More than 8 in every 10 (80%) kidney cancers. Renal cell cancer is also called renal adenocarcinoma or hypernephroma. In renal cell cancer the cancerous cells are found in the lining of the tubules (the smallest tubes inside the nephrons that help filter the blood and make urine).
There are several types of renal cell cancer that can be identified by looking at the cancer cells under a microscope. The main ones are:
• Clear cell
• Papillary (Types 1 and 2)
• Chromophobe
• Oncocytic
• Collecting duct
All these types of renal cell cancer may also occur in a different form, known as 'sarcomatoid' type.
Clear cell cancer is the most common type of renal cell cancer. The others are much less common. Often kidney cancers contain more than one of these cell types. If a kidney cancer is a sarcomatoid type it may have a worse outlook than nonsarcomatous kidney cancers. Generally, how quickly growing the cancer is likely to be is graded in a particular way, by looking at the cells under a microscope. The kidney cancer grading system is called the Fuhrman system.
All these types of renal cell cancer, and all grades, are treated the same way. The grading may give the doctor some idea of how quickly or slowly the cancer is likely to grow. It may help the doctor decide on the treatment you need. For example, for a cancer that is likely to grow quickly, a specialist may be more likely to suggest additional treatment as well as surgery to try to lower the risk of the cancer coming back.


Other types of kidney cancer
Another type of kidney cancer is called transitional cell cancer (TCC) of the renal pelvis. It is less common. About 7 or 8 out of every 100 (7 to 8 %) kidney cancers. The treatment for this type of kidney cancer is similar to the treatment for bladder cancer.
A type of kidney cancer called Wilms' tumour can affect children. This is different from kidney cancer in adults. For information about these rare types of kidney cancer look in the help and support section for organisations that produce information about kidney cancer. They will be able to give you the information you need about your type of cancer.

Tests for kidney cancer


Tests for kidney cancer
Usually, you begin by seeing your family doctor who will ask you about your general health and examine you. Your GP will ask you to give a urine sample. He or she will test the urine for small amounts of blood (haematuria) which can be a sign of kidney cancer. The doctor may also take some blood to do other tests. Your doctor should refer you to see a specialist at the hospital if you have blood in your urine. It is important that you tell the doctor if anyone else in your family has had kidney cancer.
At the hospital
The specialist will begin by asking you about your medical history and symptoms. You will have more urine and blood tests. The specialist will look at your kidneys using either an ultrasound scan, a test called an intravenous pyelogram (IVP) or a CT urogram.
If you have blood in your urine, you will probably need to have a cystoscopy so that the doctor can check inside your bladder. The doctor will use a cystoscope, which is a long, thin, flexible tube that is put into your urethra and up into the bladder. You can have a cystoscopy under local or general anaesthetic.


Usually, you begin by seeing your family doctor who will ask you about your general health and examine you.
Your GP will ask you to give a urine sample. They will test for small amounts of blood (haematuria) which can be a sign of kidney cancer. Often the amount of blood in the urine is so small that it can't be seen but it can be picked up by the test. The doctor may also take some blood to do other tests. They may do a physical examination to feel for any lumps or swelling. But because the kidneys are deep inside the body, the doctor may not be able to feel small tumours.
Your doctor should refer you to see a specialist at the hospital if you have blood in your urine. It is important that you tell the doctor if anyone else in your family has had kidney cancer. This could help the doctor decide what tests to do.
There are guidelines for GPs to help them decide who needs an urgent referral to a specialist.

Going to the hospital
The specialist will begin by asking you about your medical history and symptoms. If your urine test has picked up blood then the doctor will run more tests on your urine. You will be asked to have more blood tests.
It is important for the doctor to take a look at your kidneys with an
• Ultrasound or
• Intravenous pyelogram (IVP)
You will probably need to have a cystoscopy so that the doctor can check inside your bladder to make sure that any blood in your urine isn't coming from there.

Ultrasound scan
Ultrasound can show any growths inside the kidney.


IVP (intravenous pyelogram)
IVP is also sometimes called intravenous urogram or IVU. A dye is injected into your bloodstream during this test. Very rarely someone has an allergic reaction to this dye. If this has happened to you before, tell your doctor before the test. A short time after injection of the dye you have X-rays of the kidneys, ureters and bladder. The dye can show any growths in the tubes inside or leading from the kidneys.


CT urogram
You may have a CT urogram instead of an IVP. Or you may have both tests. For a CT urogram you have an injection of a dye into a vein and may also be asked to swallow a special liquid containing barium. Then a CT scanner takes a series of X-rays to give a detailed picture of the kidneys, ureters and bladder.


Cystoscopy
Your doctor may also want to look directly inside your bladder because this is part of the same body system as your kidneys. You might have this test if you have blood in your urine. To do this test the doctor will use a cystoscope, which is a type of telescope that is put into your urethra and up into the bladder. You can have a cystoscopy under local or general anaesthetic. You may have a cystoscopy under local anaesthetic at your first appointment because it can be done quickly and simply.


Stages of kidney cancer

Stages of kidney cancer
The stage of a cancer tells the doctor how far it has spread. Treatment is often decided according to the stage. Cancer stage can be written using number stages or using the TNM system. The T stands for tumour, the N for nodes and the M for metastases (cancer spread).
TNM stages
In stage T1 the tumour is no more than 7cm across and is completely inside the kidney. In T2 it is larger but still completely inside the kidney. In T3 it has spread to the tissues immediately surrounding the kidney. In T4 it has spread further away.
N0 means there is no cancer in any lymph nodes. In N1 the cancer has spread to one nearby lymph node only, and in N2 to more than one. M1 means the cancer has spread and M0 means it has not. If it has spread it is called advanced kidney cancer.
Number stages
Stages 1 and 2 are the same as T1 and T2, above. In stage 3 the cancer has grown into the adrenal gland, or one of the major veins nearby. It is in no more than one nearby lymph node. In stage 4 the cancer has grown into the surrounding tissues and there is more than one lymph node containing cancer cells, OR the cancer has spread to another part of the body.
Grade
The more abnormal cancer cells look under the microscope, the higher their grade. Low grade cancers usually grow more slowly and are less likely to spread.

What staging is
The stage of a cancer tells the doctor how far it has spread. The tests and scans you have to diagnose your cancer will give some information about the stage. It is important because treatment is often decided according to the stage of a cancer. There are two ways of writing cancer stage. The number stages (usually stage 1 to stage 4) and the TNM system.
The TNM system is a staging system that is common to all cancers. The T stands for tumour; the N for nodes and the M for metastases (the doctors' word for cancer spread). With this combination of letters and numbers, doctors can accurately describe the size of your cancer and whether it has spread to lymph nodes or elsewhere in the body. There is more about the TNM staging system in the stages of a cancer section.


The 'T' stages of kidney cancer
The 'T' stages are
• T0 - there is no evidence of a primary tumour in the kidney
• T1 - the tumour is no more than 7cm across and is completely inside the kidney
• T2 - the tumour is more than 7cm across, but is still completely inside the kidney
• T3 - the cancer has spread through the kidney capsule, to a major vein, the adrenal gland or other tissues immediately surrounding the kidney
• T4 - the cancer has spread further than the tissues immediately surrounding the kidney
You may hear your doctor talk about T1a or T1b. T1a means you have a tumour that is less than 4cm across. T1b means the kidney tumour is between 4 and 7cm across. This is being introduced because it is important for surgeons. If you have a smaller tumour, it may be possible to remove just the cancer and leave the rest of the kidney behind (nephron sparing surgery).



The ‘N’ stages of kidney cancer
These tell the doctor if the cancer has spread to your lymph nodes. There are four lymph node stages in kidney cancer. These are
• N0 - No cancer in any lymph nodes
• N1 - Cancer spread to one nearby lymph node only
• N2 - Cancer spread to more than one nearby lymph node
Doctors often call lymph nodes that contain cancer 'positive lymph nodes'. If you have cancer in your lymph nodes, then your kidney cancer has begun to spread. Your doctor may want you to have further treatment after your surgery.

The 'M' stages of kidney cancer
As with most cancers, there are two stages for metastases (or cancer spread). Either the cancer has spread (M1) or it hasn't (M0).


The number stages - stage 1 to stage 4
By combining the T, N & M stagings of your tumour, your doctor will give it an overall stage. This is important for deciding which treatment is best for you. There are 4 stages for kidney cancer. They are
• Stage 1 - The cancer is less than 7cm across and is completely inside the kidney
• Stage 2 - The cancer is more than 7cm across but is still completely inside the kidney
• Stage 3 - The cancer has grown into the adrenal gland, or one of the major veins nearby. There is no more than one nearby lymph node containing cancer cells
• Stage 4 - The cancer has grown into the surrounding tissues and there is more than one lymph node containing cancer cells OR the cancer has spread to another part of the body
Doctors tend to use Roman numerals for writing down cancer stage. So you may see stage written as I, II, III, or IV.


The grade of your cancer
The grade of your cancer is decided by the appearance of the cancer cells under the microscope. The more they look like normal kidney cells, the lower the grade of your cancer. The more abnormal (and so less like normal kidney cells) the cancer cells look, the higher the grade of your cancer. Generally speaking, low grade cancers tend to grow more slowly and are less likely to spread than high grade cancers.
The main factor for deciding which treatment is best for you is whether your cancer has spread away from the kidney or not.

Surgery
Surgery is the main treatment for kidney cancer that has not spread. Stage 1 and 2 kidney cancer is often cured with surgery. Even some stage 3 cancers can be cured if it is possible to remove all the cancer.
Removing a kidney is called a nephrectomy. This comes from the Greek word for kidney, ‘nephros’. You may have either the whole kidney or part of the kidney removed
• Radical nephrectomy means removing the whole kidney
• Partial nephrectomy means removing part of the kidney
Surgeons sometimes call partial nephrectomy 'nephron sparing surgery'. The nephron is the working unit of the kidney that filters the blood. So this just means that your surgeon is trying to leave some functioning kidney behind after the operation to remove the cancer. Generally, nephron sparing surgery (partial nephrectomy) is suitable for you if
• You have a small kidney tumour (the exact size limit varies, but less than 7 cm across at the very most)
• You only have one kidney, and that has a tumour in it
• You have cancer in both kidneys
• Your unaffected kidney doesn't work as well as it should
If you do not have at least one working kidney, then you will have to have kidney dialysis for the rest of your life. Dialysis is a way of doing the job your kidneys would do if they were working properly. That is, removing the waste products and extra water that you don’t need from your body.


If you can’t have surgery
It may not be possible for you to have surgery because you have other medical problems. In this case the doctor might use
• Radiotherapy
• Arterial embolisation
• Experimental treatment methods


Radiotherapy
Radiotherapy treats cancer by using high energy rays that destroy the cancer cells, while doing as little harm as possible to normal cells. It is only helpful in a relatively small number of people with cancer of the kidney. It is not often used with kidney cancer that is likely to be curable. But it can be useful for shrinking the cancer and controlling pain or bleeding. You may be offered radiotherapy after surgery if your surgeon thinks some cancer cells may have been left behind after your operation.


Biological therapy
Biological therapies are treatments that use natural substances from the body, or drugs made from these substances. Some clinical trials are using the biological therapies interferon or interleukin (IL-2) to try to stop kidney cancer from coming back after surgery. Doctors call this adjuvant treatment.


Arterial embolisation
Arterial embolisation blocks the blood vessels to the area of the kidney containing the cancer. This reduces the supply of oxygen and food to the cancer, and may make it shrink. This is not a cure, however. The cancer is not removed and there is a high chance of cells breaking away in the future and spreading to other parts of the body. Embolisation is also sometimes used before surgery to reduce the risk of bleeding.
This minor operation is done in the X-ray department. You will have to stay in hospital at least overnight, so you will be admitted to a ward. You will be asked to change into a hospital gown and will be taken to the X-ray department.
You will be asked to lie on the X-ray table. Then you will be given something to make you sleepy. The doctor will give you some local anaesthetic and then put a long tube (a catheter) into the main blood vessel in your groin. Watching on an X-ray screen, the doctor will feed the catheter up through your blood vessels until it is in exactly the right place. Then, the doctor will inject small pieces of gelatine sponge or some plastic beads into the main blood vessels that carry blood to the kidney. Then the catheter will be removed. You will have a tight dressing put on to the small wound site in your groin and you will be taken back to the ward to rest. You will not be allowed to get up for at least 4 hours in case moving around makes the wound bleed. You will be asked to stay in hospital overnight. If there is no bleeding from your groin, you will be able to go home the following day.
Side effects
You may have some pain for 12 to 24 hours following this treatment. You will be given painkillers while you are in hospital and to take home with you. If you are still having pain after the painkillers, do tell your nurse or doctor and ask for more or something stronger.
The aim of the treatment is to kill off the cancer in your kidney. When the cancer cells die off, they may release toxins into your bloodstream. These toxins can cause
• Fever
• Sweats
• Weakness and lack of energy
These side effects will wear off after a few days. At least they are a sign that your treatment is working! If you find them troublesome, try taking paracetamol every 6 hours until the side effects improve.


Experimental treatments
There are several different methods of killing (or 'ablating') kidney tumours being investigated. There is information on all these in our kidney cancer research page. They include
• Cryotherapy - freezing the tumour
• Radio frequency ablation (RFA) - killing the tumour with heat
• HIFU - high intensity ultrasound, which also produces heat to kill the tumour
These techniques can all be done in different ways. They can be used during a regular operation. But researchers and doctors are working on ways to use them that are 'less invasive'. For example, RFA may be done by putting probes through the skin so you don't have to have an operation. We must stress, though, that these are all experimental techniques. They have to be tested, and those who have taken part in trials followed up for some years, before we can be sure that they work as well as surgery to remove kidney cancer.