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Causes & diagnosis

Causes of bladder cancer

Each year about 10,000 people in the UK are diagnosed with bladder cancer. Men get bladder cancer much more commonly than women. It's rare for anyone under the age of 50 to get it but it becomes more common as people get older. Cancer of the bladder isn't infectious and can't be passed on to other people.

Some of the possible causes or risk factors for bladder cancer are known. The following risk factors can increase the risk of developing it:

Cigarette smoking This is the biggest risk factor for bladder cancer. The longer a person smokes for and the more cigarettes they smoke, the greater the risk. Chemicals that cause bladder cancer are present in cigarette smoke. It's thought that these chemicals get into the bloodstream and end up in the urine after being filtered by the kidneys. They then damage the cells which line the inside of the bladder. It takes many years for the chemicals to cause bladder cancer.

Exposure to chemicals at work The other main cause of bladder cancer is exposure to certain chemicals at work. These include chemicals previously used in dye factories, rubber, gasworks, plastics, paints and in other chemical industries. These chemicals were banned in the UK in 1967. However, it can take up to 25 years after exposure for bladder cancers to develop.

If you think that you were exposed to certain chemicals through your work, let your cancer doctor know. You may be able to claim Industrial Injuries Disablement Benefit from the Department of Work and Pensions.

Infection Repeated urinary infections and kidney or bladder stones (which can cause infections) have been linked with bladder cancer. People who are paralysed have more bladder infections and a higher risk of getting bladder cancer.

Untreated infection with a parasite called schistosoma (also called bilharzia) is a major cause of bladder cancer in people living in developing countries.

Earlier treatment for cancer Radiotherapy to the pelvis (to treat another cancer) and treatment with a chemotherapy drug called cyclophosphamide can also increase your risk.

Types of bladder cancer

Transitional cell bladder cancer (TCC) is the most common type of bladder cancer. Nearly all cancers of the bladder start in the layer of cells (transitional cells) which form the lining of the bladder (transitional epithelium). These cancers are called transitional cell or urothelial cell cancers.

Bladder cancer may appear as a tumour which has grown into the muscle wall of the bladder. This is known as invasive bladder cancer.

Bladder cancer may also begin as a small growth only on the inner lining of the bladder (called papillary cancers). Sometimes these early cancers can start to grow into the muscle of the bladder and become invasive bladder cancer.

Carcinoma in situ (CIS) is a type of early bladder cancer which appears as a red, ulcerated area in the bladder. In CIS the cells are very abnormal or high-grade, so it can grow quickly. If it's not treated effectively, there's a high risk that CIS will become an invasive cancer.

Rarer types of bladder cancer are squamous cell cancer and adenocarcinoma. Squamous cell cancers start from one of the types of cell in the bladder lining. Adenocarcinoma starts from glandular cells which produce mucus. Both of these types are usually invasive.

Symptoms and diagnosis of bladder cancer

Symptoms of bladder cancer

The most common symptoms of bladder cancer are:

Blood in the urine (haematuria) This is the most common symptom. It usually happens suddenly and may come and go. It's not usually painful. Sometimes the blood in your urine can't be seen and is picked up by a urine test.

If you ever see blood in your urine you should always go to your family doctor (GP) and get it checked out.

Bladder changes Some people may have a burning feeling when they pass urine, or need to pass urine more often or urgently. These are all symptoms of bladder irritation and are more likely to be due to an infection rather than cancer. If these symptoms don't get better with antibiotics, you might need more tests.

Most people with these symptoms won't have bladder cancer. Other more common conditions such as infection or stones in the bladder or kidneys are often the cause. But, if you develop any of these symptoms it's important to get them checked by your doctor.

How bladder cancer is diagnosed

Usually, you begin by seeing your family doctor (GP). They will ask for a sample of your urine. This will be tested in the surgery to find out if you have any blood in it. Your GP may then carry out an internal examination of your back passage (rectum) and (in women) your vagina. This is because the rectum and vagina are very close to the bladder, and it allows the doctor to feel for any obvious changes.

Your urine sample will be sent to a laboratory to be checked under a microscope for any abnormal cells. It will also be checked for infection. Your GP may also arrange for further tests or x-rays. They will need to refer you to hospital for these tests, and for expert advice and treatment from a urologist (specialist doctor who treats bladder and kidney problems).

Some people who have blood in their urine (haematuria) may be referred to a ‘one-stop' haematuria clinic. At this kind of clinic, all the tests needed to make a diagnosis can often be carried out on the same day. You may be asked not to eat or drink anything for up to eight hours before your appointment.

At the hospital

The urologist will ask you about your symptoms and general health. You will also be asked if you have any other health problems. The doctor will examine you by feeling your abdomen and bladder and you may have another internal examination. They will probably ask you to give another urine sample and take a blood sample for testing.

Some of the following tests will then be arranged for you:

Blood tests

Samples of your blood will be taken to check your general health, the number of cells in your blood (blood count), and to see how well your kidneys and liver are working.


The most important test is a cystoscopy. This is where a doctor uses a thin, flexible fibre-optic tube with a light on the end (cystoscope) to look at the inside of the bladder.

It's usually done first under a local anaesthetic, because this is the quickest and simplest way. Some people may have a sedative to help them relax. A jelly, which contains anaesthetic is squeezed into the opening of your urethra (tip of the penis or outside of the vagina). The anaesthetic will start to work after a few minutes.

The doctor will then gently pass the cystoscope into your urethra. This allows the doctor to look at the whole lining of the bladder and urethra. The whole test takes a few minutes and you can usually go home straight afterwards. You may have some soreness or mild pain when you pass urine for the first time after the test. You may notice a little blood in your urine for the first couple of days. There are not usually any other after effects.

If any abnormal area that could be bladder cancer is seen, you will be asked to come back for a cystoscopy and a biopsy (removal of a piece of tissue) on another day.

Cystoscopy and biopsy

This is sometimes done as a day-case under a general anaesthetic but you may need to stay in hospital overnight. You will be given instructions on how to prepare for the test. Under the anaesthetic, the doctor can closely examine the inside of the bladder and can take samples (tissue biopsies) of any abnormal areas. Any small growths can be removed, as they could be cancer. You can usually go home the same day. The tissue samples are sent to a pathologist (an expert who identifies diseases by looking at cells) who examines them under a microscope. If the biopsy shows that you have cancer of the bladder, you will be asked to go back to the hospital to have the cancer removed.

Further tests for bladder cancer

  • Chest x-ray
  • IVU (intravenous urogram)
  • MRI scan
  • CT scan
  • Ultrasound scan
  • Bone scan
  • Waiting for your test results

You may have some tests (IVU and ultrasound) done before your cystoscopy. Your specialist will also want you to have tests to find out how deeply the cancer has grown into the bladder and if it has spread outside the bladder. Tests may include:

Chest x-ray

This is taken to check that your lungs and heart are healthy.

IVU (intravenous urogram)

Some peo ple may have n IVU. This test shows up a nything unusua l in the bladder, ureters or kidneys (urinary system). It is done in the hospital x-ray department and takes about an hour. A dye is injected int o a vein in your arm, and travels through the bloodstream to the kidneys. T he doctor can watch on a screen how the d ye passes through the urinary system and c an pick up any problems.

The dye will make you feel hot and flus hed for a few m inutes but this feeling goes away after a sh ort time.

MRI sc an

An MRI (magnetic reson nce imaging) scan is similar to a CT scan, but uses magn etism instead of x-rays to build up cross-sectional pictures o f your body. It's used to find out how deeply the cancer has grown into the bladder and whether it has spread outside the bladder. You cannot have an MRI scan if you have any metal in your body, su ch as heart pacemakers or certain types of su rgical clips.

The scanner is a very powerful magnet, so before ent ering the room you'll need to remove any metal belongings. During the test, you will be asked to lie very still on a c ouch inside a long tube for about 30 minut es. It can be slightly uncomfort able and some people feel cl austrophobic during the scan. It is also very noisy, but you will be given earplugs or headphones. You can usually take someone with you into the room to keep you com pany.

Some peo ple are given an injection of d ye into a vein in the arm to help make the p icture clearer.

CT scan

A CT (computerised tom ography) scan takes a series of x-rays, whic h build up a three-dimensional picture of the inside of y our body. It's used to find out more about h ow far the canc er has spread. Usually you w ill have x-ray pictures taken of the che st, abdomen a nd pelvis, which are fed into a computer to give a detailed picture.

The scan is painless and takes betwee n 10 and 30 minutes. You may be asked not to eat or drin k anything for several hours before your appointment.

Most people who have a CT scan are given a drink or injection of dye before the sc an. This helps the doctor to see particular a reas more clearly. People who are allergic to iodine or have asthma may be at higher risk of reacting to the dye. If you are allergic to iodine or have asthma tell the doctor an d the person d oing the test b efore you have the injection or drink. Most p eople feel hot a nd flushed for a few minutes after having t he injection. Yo u will probably be able to go home as soon as the scan is over.


Ultrasound scan

This test can also show up anything unusual in your urinary system. It uses sound waves to build up a picture of the inside of the body.

You'll be asked to drink plenty of fluids before your test so that your bladder is full and can be seen clearly. Once you are lying comfortably on your back, a special gel is spread over the skin of your abdomen. A small device, like a microphone, is passed over the area. It gives out sound waves and picks them up as they bounce back (echoes) from the organs inside your body. The echoes are made into a picture by a computer. The scan is painless and takes about 15-20 minutes. Once it's over, you will be able to empty your bladder.

Bone scan

A bone scan can show up any abnormal areas of bone. It may be done to find out if the cancer has spread to the bones.

A very small amount of a mildly radioactive liquid will be injected into a vein, usually in your arm. Abnormal bone absorbs more of the radioactive substance than normal bone. This shows up on a scan as highlighted areas (known as hot spots).

The level of radioactivity used is very small and doesn't cause any harm.

You will have to wait for up to three hours after having the injection before you have a scan. This is to allow time for the bone to absorb the radioactive substance. It's a good idea to take a book or a magazine to help pass the time. After a few hours you will have a scan of the whole body.

A bone scan can show up conditions other than cancer such as arthritis. In this case you may need to have further tests, like an x-ray of the abnormal area. results

Waiting for your test

It will probably take several days for the results of your tests to be ready. Your results will show the stage of your cancer and help your specialist to decide on the most appropriate treatment for you.

Waiting for your results can be a difficult time. It may help you to talk things over with a relative or close friend. You may want to speak to a support organisation.

Grading and staging of bladder cancer

  • Grading
  • Staging
  • Tumour size (T)
  • Lymph nodes (N)
  • Metastases (M)


Grading refers to the appearance of the cancer cells under the microscope. The grade gives an idea of how quickly the cancer may develop. The most common grading system uses three grades:

  • grade 1 (low grade)
  • grade 2 (moderate grade)
  • grade 3 (high grade)

Low grade means that the cancer cells look very much like normal bladder cells. They are usually slowly growing and less likely to spread. In high-grade tumours the cells look very abnormal. They are likely to grow more quickly and are more likely to spread. In bladder cancer, carcinoma in situ (CIS) is always high grade.

Grading is important in early bladder cancer. It helps your doctor decide if you need extra treatment after the cancer has been removed.


The stage of a cancer describes its size and whether it has spread. Once your doctors know the stage of the cancer they can decide on the most appropriate treatment for you.

The most commonly used staging system for bladder cancer is called the TNM system:

  • T is the size of the tumour (cancer)
  • N is whether it has spread to the nearby lymph nodes (sometimes called glands)
  • M is whether the cancer has spread to other parts of the body (metastases).

Tumour size (T)

Early or superficial bladder cancer

  • CIS CIS (carcinoma in situ) is sometimes described as a flat tumour. Cancer cells are only in the inside layer of the lining of the bladder.
  • Ta There is a small area of cancer only in the bladder lining.
  • T1 The cancer has started to grow into the layer of connective tissue beneath the bladder lining.

Invasive bladder cancer

  • T2 The cancer has started to grow into the muscle of the bladder wall under the connective tissue layer.
  • T2a The cancer has grown through the superficial muscle.
  • T2b The cancer has grown deeply into the muscle.
  • T3 The cancer has grown through the whole layer of muscle.
  • T3a The cancer has grown into the fat layer (beneath the muscle). This can only be seen when the tissue is examined under a microscope (microscopic).
  • T3b The cancer can be seen in the fat layer (macroscopic).

Locally advanced bladder cancer

  • T4 The cancer has spread outside the bladder to any of the following: the prostate, womb and vagina, pelvic or abdominal wall.
  • T4a The cancer has spread to the prostate, womb or vagina.
  • T4b The cancer has spread to the pelvic or abdominal wall.

Diagram showing the different tumour sizes in the bladder

Lymph nodes (N)

The N refers to whether the cancer cells have spread into the lymph nodes close to the bladder. There are four lymph node stages:

  • N0 There are no cancer cells in any lymph nodes.
  • N1 There are cancer cells in one lymph node smaller than 2cm across.
  • N2 There are cancer cells in one affected lymph node larger than 2cm, but smaller than 5cm, or more than one node affected, but all of them smaller than 5cm across.
  • N3 There are cancer cells in at least one affected lymph node larger than 5cm across.

If the cancer cells have spread to the lymph nodes, the nodes are described as positive.

Metastases (M)

If the cancer cells have not spread, this is described as M0.

M1 is when the cancer cells have spread to other parts of the body. This is called secondary, metastatic or advanced bladder cancer. If bladder cancer spreads, it's most likely to go to the bones, the lungs or the liver.

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