What is the best test to detect kidney cancer?

Seeing a GP

The GP may:

• ask you about your symptoms
• examine you to feel for any lumps or swelling
• test a sample of your pee for infections or blood – any blood will not always be visible to the naked eye
• arrange for a blood test to check for signs of a kidney problem

These checks may help diagnose or rule out some possible causes of your symptoms, such as a urinary tract infection (UTI).

If the GP thinks you need further assessment, they can refer you to a hospital specialist. If you need to be referred urgently, you'll usually be seen within 2 weeks.

Tests for kidney cancer

These tests can confirm or rule out kidney cancer. If you have cancer, they can help show whether it has spread to other parts of your body.

The tests you might have include:

• an ultrasound scan – a scan that uses high frequency sound waves to create an image of your kidneys so your doctor can see any problems
• a CT scan – a detailed scan where several X-rays are taken and then put together by a computer; you may be given an injection of a dye beforehand so your kidneys can be seen more clearly
• an MRI scan – a scan that uses strong magnetic fields and radio waves to produce a detailed image of your kidneys
• a cystoscopy – where a thin tube is passed up your urethra (the tube that carries urine out of your body) so your doctor can see any problems in your bladder
• a biopsy – where a needle is inserted into your kidney to remove a small tissue sample for analysis in a laboratory; local anaesthetic is used to numb the area so the procedure should not hurt
• a PET scan – a detailed body scan that can be helpful for investigating confirmed cases of kidney cancer to see if the cancer has spread and how well it's responding to treatment

Stages of kidney cancer

If you're diagnosed with kidney cancer, it will usually be given a "stage". This is a number that describes how far the cancer has spread.

Doctors use the TNM system to stage kidney cancer. This consists of 3 numbers:

• T (tumour) – from 1 to 4, depending on the size of the tumour
• N (node) – from 0 to 2, depending on whether the cancer has spread to nearby lymph glands
• M (metastases) – either 0 or 1, depending on whether the cancer has spread to another part of the body

Cancer Research UK has more information about the stages of kidney cancer.

Coping with the diagnosis

Being diagnosed with cancer can be very distressing. The news can be difficult to take in and make sense of.

Talking to your friends or family may help, although you might also find it useful to speak to a counsellor, a psychiatrist or other people in a similar situation to you.

Diagnosing kidney cancer starts with your healthcare provider asking you questions. They will ask about your health history, your symptoms, risk factors, and family history of disease.

Your healthcare provider will also give you a physical exam. You may be checked for a fever and high blood pressure. The healthcare provider may feel your belly (abdomen), sides, and back for lumps.

What tests might I need?

Symptoms of kidney cancer can be caused by other less serious problems. Because of this, you will likely have some tests. Unlike most types of cancer, kidney cancer can often be diagnosed without a biopsy. A biopsy is when small pieces of tissue are removed and looked at with a microscope. Instead, you may have 1 or more of the following:

• Urine test

• Blood tests

• CT scan

• MRI scan

• Ultrasound

• Intravenous pyelogram (IVP)

• Angiography

• Fine needle aspiration or biopsy 

Urine test

About 2 out of 5 people with kidney cancer, where the cancer has invaded the kidneys' collecting system, have blood in their urine. But there are many conditions that may cause blood in the urine. Check with your healthcare provider. Blood in the urine can be found by doing a test called a urinalysis. For this test, a small sample of your urine is tested in a lab to see if it has blood. Your provider may do a special kind of urine test (urine cytology). It checks for cancer cells in the urine.

Blood tests

There is no blood test that can diagnose kidney cancer. But a complete blood count (CBC) and blood chemistry test can show signs in the blood that are linked with kidney cancer. For example:            

• Too few red blood cells. This condition is called anemia. It is common in many kinds of cancer. 

• Too many red blood cells.  This condition is called erythrocytosis or polycythemia. Some types of kidney cancer cells make a hormone called erythropoietin. This causes bone marrow to make too many blood cells.

• A high blood calcium level.  This may show that the cancer has begun to affect the bones.  

• A high level of liver enzymes.  This may be a sign that the cancer has spread to the liver.

Imaging Tests

CT scan

A CT scan uses a series of X-rays and a computer to make detailed images of the inside of the body. This test can confirm a diagnosis of kidney cancer. During the test, you lie still on a table as it slides into a CT scanner. A CT scan is painless. You may be asked to hold your breath 1 or more times during the scan.

In some cases, you will be asked to drink a contrast dye 4 to 6 hours before the scan. Then you may be asked not to eat anything until a second set of pictures is taken. The dye lets your healthcare provider see certain parts of the body more clearly. The dye will pass through your body and exit through your bowel movements. Dye may be given by injection into a vein as well. When the dye is injected, you may have a warm feeling from your chest to your groin. Tell your healthcare provider if you have ever had a reaction to contrast dye. This includes hives, trouble breathing, or becoming suddenly hot. Special medicines can be given before the test to help prevent these kinds of reactions.

MRI scan

An MRI uses radio waves, large magnets, and a computer to create detailed images of the body. An MRI can show if cancer has spread to your spine or brain.

During the test, you lie still on a table as it passes into a scanner tube. If you can’t handle small, enclosed spaces (claustrophobic), you may be given a sedative before having this test. The scanner takes 2 to 15 minutes to make an image. You may need more than 1 set of images. The test may last an hour or more. An MRI test is painless. But it is noisy. You can bring earphones and an MP3 device, or ask for earplugs.

Ultrasound

An ultrasound test uses sound waves to create images on a computer screen. A gel is put on the skin of your lower back. A technician then uses a handheld wand (called a probe or transducer) to press on the skin above your kidneys. This test can help show if a kidney tumor is a fluid-filled sac (cyst) or a solid tumor. A solid tumor is more likely to be cancer.

Intravenous pyelogram (IVP)

This test uses a special dye and X-rays to look at the kidneys, ureters, and bladder. During this test, your healthcare provider injects dye into 1 of your veins. X-rays are taken as the dye passes through your urinary tract. With the help of the dye, your healthcare provider can see abnormal things, tumors, kidney stones, or any blocked areas that may be caused by kidney cancer. The test can also check the blood flow through the kidneys. 

Angiography

This test is very much like an IVP. It uses dye and X-rays to look at the kidneys. With angiography, the dye is injected directly into an artery that goes to your kidney. The test helps show the blood vessels and lets your healthcare provider see which blood vessels are sending blood to the tumor. This test can also help your healthcare provider see if the tumor can be taken out by surgery.

Biopsy

Fine needle aspiration (FNA) or biopsy

A biopsy is a test to take small pieces of tissue from the body. The tissue is then looked at with a microscope. A biopsy is not often done for kidney cancer. In most cases, imaging tests and surgery give all the information needed to diagnose and treat the cancer. But in some cases, a biopsy may be done to confirm a diagnosis of kidney cancer. It can also give more information to help your healthcare provider decide which treatment is best.

During a biopsy, your skin is numbed. A thin needle is then inserted through your skin to remove fluid or small pieces of tissue from your kidney. Your healthcare provider then sends the sample to a specialist, called a pathologist. The pathologist then looks for abnormal cells under a microscope. It often takes several days for the results of a biopsy to come back.

The difference between an FNA and a biopsy can be subtle. An FNA involves sucking (aspirating) a small amount of tissue or fluid through a needle using a syringe. The needle used for FNA biopsy is thinner than the ones used for routine blood tests. The needle used in core biopsies is larger than that used in an FNA. It removes a small cylinder of tissue.  

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