If your doctors cannot tell from other tests whether the kidney tumour is cancer, they might take a small piece of tissue from the tumour. This is called a biopsy.
They might take a biopsy if you have kidney cancer that has spread.
How you have it
Your doctor uses an ultrasound or CT scanner to help them see exactly where the tumour is.
You lie on your front on a couch or bed to have the biopsy. The doctor cleans the skin over the kidney with antiseptic. They inject local anaesthetic into the area to make it numb. This may sting a little at first.
A hollow needle goes through the skin and muscle into the kidney tissue. They take a small sample. You might feel some pressure at this time.
You need to hold your breath for 5 to 10 seconds while the needle is pushed in and out. This is because the kidneys move slightly when you breathe in and out. Your doctor tells you exactly when to hold your breath.
After the biopsy
After the biopsy you need to lie on a bed for several hours, to make sure you have no bleeding. You might want to take in a book or electronic device for entertainment.
You may need to stay in hospital overnight. If you have the biopsy early in the morning, you may be able to go home later on the same day.
The biopsy area may be sore and uncomfortable for a while. Your nurse will give you mild painkillers.
Getting your results
The result of your biopsy may take a week or so to come back.
Waiting for results can be an anxious time. You might find it useful to talk to someone close to you.