Kidney cancer

More than 3000 Australians are diagnosed with kidney cancer each year. It makes up about 2.5% of all cancers and is the 10th most common cancer in Australia. The risk of kidney cancer increases with age, and it is rare in people under 40. Men are almost twice as likely to be diagnosed with kidney cancer as women are.

Types of renal cell carcinoma (RCC)

There are several types of renal cell carcinoma, based on the way the cells look under the microscope. The most common RCC is clear cell carcinoma.

Other types of kidney cancer

RCC is the most common type of kidney cancer, but there are other types.

An uncommon type is urothelial carcinoma (or transitional cell carcinoma). This can begin in the ureter or in the renal pelvis, where the kidney and ureter meet. Urothelial carcinoma of the kidney or ureter behaves and is treated like bladder cancer (another type of urothelial cancer), rather than like RCC. For more information, read Understanding Bladder Cancer.

Very rarely, cancer in the kidney can be a secondary cancer (metastasis) from a primary cancer located in another part of the body. However, this type of cancer is not kidney cancer and it behaves more like the original cancer.

The most common type of kidney cancer in younger children is called Wilms tumour (or nephroblastoma), but this is still a rare cancer. Visit Cancer Australia’s website to learn more.

Several factors may increase the risk of a person developing kidney cancer:

• Smoking – People who smoke have almost twice the risk of developing kidney cancer as nonsmokers. Up to one-third of all kidney cancers are thought to be related to smoking.
• Obesity – Excess body fat may cause changes in certain hormones that can lead to kidney cancer.
• High blood pressure – Whether it is caused by being overweight or another medical condition, high blood pressure increases the risk of kidney cancer.
• Kidney failure – People with end-stage kidney disease have a higher risk of developing kidney cancer.
• Family history – People who have family members with kidney cancer, especially a sibling, are at increased risk.
• Inherited conditions – About 3–5% of kidney cancers occur in people with particular inherited syndromes, including von Hippel-Lindau disease, hereditary papillary RCC and Birt-Hogg-Dubé syndrome.
• Exposure to toxic substances at work – The risk may be higher after regular exposure to certain chemicals, such as some metal degreasers, arsenic or cadmium.

The kidneys are two bean-shaped organs, each about the size of a fist, and are part of the urinary system. They are deep inside your abdomen, positioned near the middle of your back, on either side of the spine.

Blood filtering – The main role of the kidneys is to filter and clean the blood. Blood goes into each kidney through the renal artery and is filtered through millions of tiny sieves called nephrons. It then goes back into the rest of the body through the renal vein.

The urinary system – As part of the body’s urinary system, the kidneys filter the blood. They remove excess water and waste products and turn these into urine. Urine travels from each kidney into a funnel called the renal pelvis, then through a tube called the ureter, and into the bladder.

Urine is stored in the bladder until urination, when it leaves the body through a tube called the urethra. In women, the urethra is a short tube in front of the vagina. In men, the tube is longer and passes through the prostate and penis.

Hormone production – The kidneys’ main function is to cleanse the blood, but they also help your body control how much blood it needs. They do this by producing hormones that trigger the production of red blood cells and help regulate blood pressure.

Adrenal glands – An adrenal gland sits above each kidney (‘ad’ means above, and ‘renal’ means kidney). The adrenal glands produce a number of hormones. Although these glands are not part of the urinary system, kidney cancer can sometimes spread to them.