Tests
Most kidney cancers are found by chance (incidentally) when a person has an ultrasound or another imaging scan for an unrelated reason. If your doctor suspects early or advanced kidney cancer, you may have some of the following tests, but you are unlikely to need them all.
Blood and urine tests
You will probably have urine and blood tests to check your general health and look for signs of a problem in the kidneys. These tests do not diagnose kidney cancer. They may include:
- a complete count of the three types of blood cells – red blood cells, white blood cells and platelets
- tests to check how your kidneys are working
- blood chemistry tests to measure certain chemicals – high levels of the enzyme alkaline phosphatase could be a sign that kidney cancer has spread to the bones.
Imaging scans
You will usually have at least one of the following imaging scans:
- Ultrasound – soundwaves are used to produce pictures of your internal organs. These might show if there is a tumour in your kidney. An ultrasound is painless and takes about 15–20 minutes.
- CT scan – if kidney cancer is suspected on an ultrasound, you will usually have a CT scan, which uses x-ray beams to create detailed, cross-sectional picture of the inside of your body. It is painless and takes about 30–40 minutes. This will help find any tumours in the kidneys, and provide information about the size, shape and position of a tumour. The scan also helps check if a cancer has spread to nearby lymph nodes or to other organs and tissues.
- MRI scan – uses a powerful magnet and radio waves to create 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 cancer has spread from the kidney to the renal vein or spinal cord. The MRI scan may take between 30 and 90 minutes.
- Radioisotope bone scan – can look for changes in the bones. It’s used only if you have bone pain or blood tests results show high levels of alkaline phosphatase. These may be a sign that the cancer has spread to the bones. If cancer is found in the bones, the scan can also be used to check how the cancer is responding to treatment. After the scan, you need to drink plenty of fluids and you should avoid contact with young children and pregnant women for the rest of the day, as it uses a very small amount of a radioactive solution.
- PET scan – uses an injection of a small amount of radioactive solution to help cancer cells show up brighter on the scan. It is useful for some cancers, but kidney cancer does not always show up well. Newer solutions are currently being studied.
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), ureters (ureteroscopy) and kidneys (ureterorenoscopy). These procedures rule out urothelial carcinoma of the bladder, kidney or ureters, but they may not be needed if an ultrasound and CT scan have already shown there is a tumour on your kidney.
Before having scans, tell the doctor if you have any allergies or have had a reaction to contrast during previous scans. You should also let them know if you have a pacemaker, diabetes or other kidney disease, or are pregnant. Your treatment team will discuss any precautions with you.
Tissue biopsy
A biopsy involves removing a tissue sample for examination under a microscope. It is a common way to diagnose cancer, but it is not often needed for kidney cancer before treatment. This is because imaging scans are good at showing if a kidney tumour is cancer.
For many people with kidney cancer, the main treatment is surgery. In this case, the tumour removed during surgery is tested to confirm that it is cancer. A biopsy may be done before treatment when:
- surgery is not an option because the tumour is very small and active surveillance is suggested – a biopsy will help work out what other treatment is needed
- the tumour is large, looks irregular on the scan, or has obviously spread to the renal vein, adrenal gland or nearby lymph nodes.
If a biopsy is done, it will be a core needle biopsy, which usually takes about 30 minutes. The tissue sample will be sent to a laboratory, where a specialist doctor called a pathologist will check for any cell changes.
In some cases, a kidney tumour will turn out to be benign (not cancer). Benign kidney growths, including oncocytoma and angiomyolipoma, can cause problems, and treatment may be similar to the treatment for early kidney cancer.
Grading and staging
Grading kidney cancer
By examining a tissue sample taken during a biopsy or after surgery, doctors can see how similar the cancer cells look to normal cells and estimate how fast the cancer is likely to be growing. This is called grading. It helps the doctors decide what follow-up treatment 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 newer system called the International Society of Urological Pathology (ISUP) system has been introduced. Both systems grade kidney cancer from 1 to 4, with grade 1 being the slowest growing and grade 4 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).
In Australia, the TNM (tumour–nodes–metastasis) system is the method most often used for staging kidney cancer. Your doctor will consider the results of your tests to give your cancer a stage of 1 to 4:
- stages 1–2 are considered early kidney cancer
- stages 3–4 are considered advanced kidney cancer.
Prognosis
Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis with your doctor, but it is not possible for anyone to predict the exact course of the disease. Your doctor can give you an idea about common issues that affect people with kidney cancer. The stage of the cancer is the main factor in working out prognosis.
In most cases, the earlier that kidney cancer is diagnosed, the better the chance of successful treatment. If the cancer is found 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 kidney cancer tend to have better outcomes. Other factors such as your age, general fitness and medical history also affect prognosis.
Understanding Kidney Cancer
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Expert content reviewers:
A/Prof Daniel Moon, Urologic Surgeon, Australian Urology Associates, and Honorary Clinical Associate Professor, The University of Melbourne, VIC; Polly Baldwin, 13 11 20 Consultant, Cancer Council SA; Ian Basey, Consumer; Gregory Bock, Urology Cancer Nurse Coordinator, WA Cancer and Palliative Care Network, North Metropolitan Health Service, WA; Tina Forshaw, Advanced Practice Nurse Urology, Canberra Health Services, ACT; Dr Suki Gill, Radiation Oncologist, Sir Charles Gairdner Hospital, WA; Karen Walsh, Nurse Practitioner, Urology Services, St Vincents Private Hospital Northside, QLD; Dr Alison Zhang, Medical Oncologist, Chris O’Brien Lifehouse and Macquarie University Hospital, NSW.
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The information on this webpage was adapted from Understanding Kidney Cancer - A guide for people with cancer, their families and friends (2020 edition). This webpage was last updated in September 2021.