Diagnosing kidney cancer

Tuesday 1 November, 2016

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On this page: Imaging scans | Tissue biopsy | Grading kidney cancer | Staging kidney cancer | Prognosis | Key points


Most kidney cancers are found unexpectedly – for example, when people have an ultrasound or scan for symptoms that turn out to be unrelated. If your doctor suspects kidney cancer, you may have some of the following tests, but you are unlikely to need all of them.

You will probably have urine and blood tests to check for changes that could be caused by kidney cancer, but these tests cannot provide a definite diagnosis. The main tests for diagnosing kidney cancer are imaging scans (see below) and tissue sampling (biopsy). Sometimes the doctor will also recommend an internal examination of the bladder (cystoscopy).

It may take up to a week to receive your test results. If you feel anxious while waiting for test results, try talking to a close friend or relative, or call Cancer Council 13 11 20 for support.

Imaging scans

You will usually have at least one of the following imaging scans.

Ultrasound

In an ultrasound, soundwaves are used to produce pictures of your internal organs. These might show if a mass is present in your kidney.

For this scan, you will lie down and a gel will be spread over your abdomen or back. A small device called a transducer is passed over the area. The transducer sends out soundwaves that echo when they encounter something dense, like an organ or tumour. The ultrasound is painless and takes about 15–20 minutes.

Early and advanced kidney cancer

Some kidney cancers are diagnosed when they have already spread beyond the kidney (advanced kidney cancer). This may be because the primary cancer never caused obvious symptoms. The tests discussed in this section are used for diagnosing both early and advanced kidney cancer. The treatments are covered in separate sections:

CT scan

A CT (computerised tomography) scan is a procedure that uses x-rays to take many pictures of the inside of your body and then compiles them into one detailed, cross-sectional picture.

If a kidney cancer is suspected on an ultrasound, your doctor will usually recommend a CT scan. This will help identify any tumours in the kidneys, provide information about tumour size, shape and position, and may show whether cancer has spread to other organs and tissues. The scan also helps identify enlarged lymph nodes that might contain cancer. Lymph nodes are small glands found in many parts of the body. If cancer is going to spread, it often spreads first to nearby lymph nodes.

As part of the procedure, you may have an injection of a dye (called contrast) into one of your veins before the scan. This dye travels through your bloodstream to the kidneys, ureters, bladder and other organs, and helps make the pictures clearer. It might make you feel flushed and hot for a few minutes. Symptoms should ease quickly, but tell the medical team if you feel unwell. The contrast should be used only if your kidneys are functioning well, so this will have been checked during earlier blood tests.

For the scan, you will need to lie still on a table that moves in and out of the CT scanner, which is large and round like a doughnut. The whole procedure takes about 30–45 minutes.

The dye used in a CT scan usually contains iodine. If you have had an allergic reaction to iodine or dyes during a previous scan, let your medical team know beforehand. You should also tell them if you are diabetic, have kidney function problems or are pregnant.

MRI scan

An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to build up detailed, cross- sectional pictures of the inside of your body. Only a few people with kidney cancer need an MRI, but it might be used to check whether the cancer has spread to the renal vein or spinal cord.

Let your medical team know if you have a pacemaker, as the magnet can interfere with some pacemakers. As with a CT scan, a dye might be injected into your veins before an MRI scan. An MRI without dye may be used instead of a CT scan if you have pre-existing kidney problems.

During the scan, you will lie on an examination table inside a large metal tube that is open at both ends. The noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may become distressed, mention it beforehand to your medical team. You may be given a medicine to help you relax, and you will usually be offered headphones or earplugs. The MRI scan may take between 30 and 90 minutes.

Radioisotope bone scan

A radioisotope scan is another way to see if any cancer cells have spread to the bones. You might have this test if you have a very large tumour or advanced kidney cancer. The scan is also used during treatment to determine how the cancer is responding to the treatment.

A very small amount of radioactive substance is injected into a vein, usually in your arm. You will need to wait while the substance moves through your bloodstream to your bones, which can take about 3–4 hours. Your body will be scanned with a machine that detects radioactivity. A larger amount of radioactivity will show up in any areas of bone affected by cancer cells. Radioisotope bone scans generally do not cause any side effects. However, tell your doctor if you are pregnant, as it may not be safe for you to have this type of scan.

The amount of radioactive substance used for this bone scan is small and disappears from your body within a few hours. After the scan, you should drink plenty of fluids and avoid contact with young children and pregnant women for the rest of the day. Your treatment team will discuss these precautions with you.

If you have blood in your urine, your doctor might use a thin tube with a light and camera to look inside your bladder (cystoscopy) and ureters (ureteroscopy). These procedures rule out urothelial carcinoma of the bladder, kidney and ureters, but they may not be needed if an ultrasound has already shown a tumour on your kidney.

Tissue biopsy

A biopsy is when doctors remove a sample of tissue from the body so that it can be examined under a microscope to see if there have been any changes in the cells.

The biopsy used to check for kidney cancer is called a core needle biopsy and is performed by an interventional radiologist during an ultrasound or CT scan. You will have a local anaesthetic to numb the area, and then a sample of tissue will be removed from the kidney with a needle. The procedure usually takes about 30 minutes.

Do I need a biopsy?

A diagnosis of kidney cancer cannot be positively made without looking at some of the tumour under a microscope. A core needle biopsy can provide a tissue sample for examination.

You may not need a biopsy if the doctor already knows enough from other tests, such as a CT scan, to immediately recommend surgery to remove the tumour. In this case, the removed tissue can then be tested to confirm that it is cancer. Surgery without a biopsy first is most likely to be recommended if the tumour is large, looks irregular on the scan, or has obviously spread to the renal vein, adrenal gland or nearby lymph nodes.

In some cases, a mass on your kidney will turn out to be benign (not cancer). If the mass is confined to the kidney and is smaller in size, a biopsy can allow doctors to make a diagnosis. A benign mass may not need surgery at all. Benign growths on the kidney can include oncocytoma and angiomyolipoma.

A biopsy may also be done if there is a suspicion that a kidney cancer has spread, and the plan is to use targeted therapy or immunotherapy rather than surgery. The biopsy helps plan treatment and may be required by the Pharmaceutical Benefits Scheme (PBS), which subsidises the cost of the drugs.

Grading kidney cancer

By examining a tissue sample taken during a biopsy or surgery, doctors can see how similar the cancer cells look to normal cells and estimate how fast the cancer would grow without any treatment. This is called grading. It helps them decide what follow-up you might need and whether to consider a clinical trial.

There are different systems for grading kidney cancer. The Fuhrman system has been widely used in Australia, but a new system called the ISUP (International Society of Urological Pathology) system has now been introduced. Both systems grade kidney cancer from 1 to 4, with grade 1 indicating the slowest growing and grade 4 indicating the fastest growing.

Staging kidney cancer

The stage of a cancer describes how large it is, where it is, and whether it has spread in the body. Knowing the stage of the kidney cancer helps doctors plan the best treatment for you. The stage can be given before surgery (clinical staging), but may be revised after surgery (pathologic staging).

If you have kidney cancer, your doctor will use the results of the tests described above to assign a stage of I–IV. Stages I–II are considered early kidney cancer, and stages III–IV are considered advanced. The diagrams opposite explain staging in more detail.

Prognosis

Prognosis means the expected outcome of a disease. It is not possible for anyone to predict the exact course of the disease, but your medical team can give you an idea about common issues that affect people with kidney cancer.

The stage of the cancer is the main factor in determining prognosis. In most cases, the earlier that kidney cancer is diagnosed, the better the chance of successful treatment. If the cancer is discovered after it has spread to other parts of the body, it is very unlikely that all of the cancer can be removed, but treatment can often keep it under control.

People who can have surgery to remove the cancer tend to have better outcomes. However, other factors such as your age, general fitness and medical history also affect prognosis.

How kidney cancer is staged

In Australia, the TNM system is the method most often used for staging kidney cancer. The TNM gives numbers to the size of the tumour (T1–4), whether or not lymph nodes are affected (N0 or N1), and whether the cancer has spread or metastasised (M0 or M1). Based on the TNM numbers, the doctor then works out the cancer’s overall stage (I–IV).

Stage I

The cancer is confined to the kidney and measures less than 7 cm.

Stage 1 kidney cancer
Stage II

The cancer is larger than 7 cm, may have spread to the renal vein or the outer tissue of the kidney but no further, and has not spread to any lymph nodes.

Stage 2 kidney cancer
Stage III

The cancer is any size and has spread to nearby lymph nodes, or the cancer has spread to the adrenal gland.

Stage 3 kidney cancer
Stage IV

The cancer has spread beyond the kidney, adrenal gland and nearby lymph nodes, and is found in more distant parts of the body, such as the abdomen, distant lymph nodes, or organs such as the liver, lungs, bone or brain. Stage IV may also be called metastatic kidney cancer.

Key points

  • Kidney cancer is most often discovered during a test or scan for an unrelated reason.
  • Sometimes kidney cancer causes blood in the urine or pain in the side, but it often doesn’t produce any symptoms. This means cancer might be present for some time before diagnosis and some kidney cancers have already advanced by the time they are diagnosed.
  • The main tests for diagnosing kidney cancer are imaging scans (ultrasound, CT, MRI and/or bone scans) and tissue sampling (biopsy). Your doctor may also arrange blood and urine tests.
  • The tests show what type of kidney cancer you have, as well as its grade and stage.
  • The grade of the cancer indicates how quickly the cancer was growing. The Fuhrman system and ISUP system both grade kidney cancer using grades 1 to 4.
  • The stage of the cancer shows if and how far the cancer has spread in the body. Kidney cancer is assigned a stage (I–IV) using the TNM system. TNM stands for tumour, nodes, metastasis.
  • Knowing the stage and the grade helps doctors recommend the best treatment for you.
  • Your prognosis is the expected outcome of the disease. It is based on the cancer’s stage, and factors such as your age, medical history and fitness. Your doctor can discuss your prognosis with you.
  • You will usually be cared for by a urologist or oncologist and other health professionals who work together as a multidisciplinary team.

Reviewed by: Dr Craig Gedye, Medical Oncologist, Calvary Mater Hospital, Newcastle, and Senior Conjoint Lecturer, School of Biomedical Sciences and Pharmacy, The University of Newcastle, NSW; Gregory Bock, Urology Cancer Nurse Coordinator, WA Cancer and Palliative Care Network, WA; A/Prof Declan Murphy, Urologist, Chair of Uro-Oncology and Director of Robotic Surgery, Peter MacCallum Cancer Centre, VIC; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA, WA; Jodie Turpin, Consumer.