Most kidney cancers are found when people have an ultrasound or scan for an unrelated reason. If your doctor suspects kidney cancer, you may have some of the following tests, but you are unlikely to need them all.
You will probably have urine and blood tests to see how well your kidneys are working and 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 and tissue sampling. Sometimes the doctor will also recommend an internal examination of the bladder, ureters and kidneys.
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.
You will usually have at least one of the following imaging scans.
In an ultrasound, soundwaves are used to produce pictures of your internal organs. These might show if there is a tumour 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. An ultrasound is painless and takes about 15–20 minutes.
A CT (computerised tomography) scan uses x-rays to take many pictures of the inside of your body and then a computer compiles them into one detailed, cross-sectional picture.
If 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.
Before the scan, you may have an injection of a dye (called contrast) into one of your veins to help make the scan pictures clearer. This dye travels through your bloodstream to the kidneys, ureters, bladder and other organs. It might make you feel flushed and hot for a few minutes. This side effect 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. If you are concerned about having the dye, check with the doctor that it is safe to have the dye injection with your level of kidney function.
For the scan, you will need to lie still on a table that moves in and out of the CT scanner, which is a large, doughnut-shaped machine. The whole procedure takes about 30–45 minutes.
An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to build up detailed, crosssectional 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 and are concerned about having the dye.
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 used to see if any cancer cells have spread to the bones. It may also be called a nuclear medicine bone scan or simply a bone scan. You might have this test if other scans show you have a very large tumour or advanced kidney cancer. The scan is also used to check 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 through your urine 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.
Removing a tissue sample from the kidney for examination under a microscope is the only way to confirm a diagnosis of kidney cancer. This is known as a biopsy. The procedure used to check for kidney cancer is called a core needle biopsy.
You will have a local anaesthetic to numb the area, and then an interventional radiologist will insert a hollow needle through the skin. They will use an ultrasound or CT scan to guide the needle to the kidney and remove a sample of tissue. The procedure usually takes about 30 minutes.
The tissue sample will be sent to a laboratory, and a specialist doctor called a pathologist will examine the sample under a microscope to see if there have been any changes in the cells. You may not need a core needle 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, rather than testing a tissue sample, the removed tumour is 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 tumour on your kidney will turn out to be benign (not cancer). If it is confined to the kidney and is smaller in size, a biopsy of the tumour can allow doctors to make a diagnosis. Benign kidney growths, including oncocytoma and angiomyolipoma, can cause problems, and treatment may be similar to early kidney cancer. A biopsy may also be done if your doctor suspects that the cancer has spread, and the plan is to treat it with ablation techniques, targeted therapy or immunotherapy, rather than surgery. The biopsy results will help your doctors identify suitable drug therapies.
This website page was last reviewed and updated November 2019
Information reviewed by: A/Prof Declan Murphy, Urologist and Director of Genitourinary Oncology, Peter MacCallum Cancer Centre, VIC; Dr Carole Harris, Medical Oncologist, St George and Sutherland Hospitals, and Clinical Lecturer, The University of New South Wales, NSW; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; A/Prof Shankar Siva, Radiation Oncologist, Peter MacCallum Cancer Centre, VIC; Beth Stone, Consumer.