The kidneys are two bean-shaped organs, each about the size of a fist. They are positioned near the middle of your back, on either side of the backbone (spine).
The kidneys are part of the body’s urinary system. Their main role is to filter and clean blood by removing excess water, salts and waste products. These filtered materials are turned 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.
In each kidney there are about one million small units called nephrons, which filter blood.
The kidneys also produce hormones, which trigger the production of red blood cells, and control the body’s calcium levels.
An adrenal gland, which produces hormones, sits above each kidney. Although adrenal glands are not part of the urinary system, cancer can spread to them.
Kidney cancer is a type of cancer that starts in the cells of the kidney.
In the early stages, the primary cancer forms a tumour that is confined to the kidney. As the cancer grows, it may invade organs or structures near the kidney, such as the surrounding fatty tissue, veins, adrenal glands, ureters or liver. It might also spread to other parts of the body, such as the lungs or bones.
Sometimes 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 like the cancer in the original organ where it started.
About nine out of 10 kidney cancers are renal cell carcinoma (RCC), sometimes called renal adenocarcinoma. Usually only one kidney is affected, but in rare cases, both can be affected. This might be because the RCC has spread to the other kidney, or sometimes because more than one RCC has occurred in the same person.
There are different types of RCC. The most common is clear cell carcinoma, based on the way the cells look under the microscope. Other less common RCCs include papillary, chromophobe and other rarer types.
Other types of kidney cancer Urothelial carcinoma (or transitional cell carcinoma) is a rare type of kidney cancer that can begin in the renal pelvis, where the kidney and ureter meet. It can also occur in the ureter, where it would be treated as cancer of the ureter or ureteral carcinoma. It tends to behave more like bladder cancer (another type of urothelial cancer) and not like RCC.
This secion has information about RCC. To find out about other types of kidney cancer, call Cancer Council 13 11 20 .
Most people with kidney cancer have no symptoms and are often diagnosed with the disease when they see the doctor for another reason. Symptoms can, however, include:
You might also have a low red blood cell count (anaemia), a high red blood cell count or high levels of blood calcium.
Sometimes these symptoms can cause fatigue and dizziness, which are related to hormones the kidney produces.
The symptoms listed above can also occur with other illnesses. Having some of these symptoms doesn’t necessarily mean you have kidney cancer – only tests can confirm the diagnosis. If you are concerned, make an appointment with your general practitioner (GP).
The exact causes of kidney cancer are not known. However, several factors are known to increase the risk of developing kidney cancer:
About 2700 people are diagnosed with kidney cancer each year. This accounts for about 2.5% of cancers in Australia.
Kidney cancer is the ninth most common cancer in Australia.
The average age of a person who gets kidney cancer is 63. Men are almost twice as likely to be diagnosed with kidney cancer as women are.
Reviewed by: A/Prof Manish Patel, Urological Cancer Surgeon, University of Sydney and Westmead and Macquarie University Hospitals, NSW; Prof Ian Davis, Professor of Medicine and Head of Eastern Health Clinical School, Faculty of Medicine and Nursing and Health Science, Monash University, and Senior Medical Oncologist, Eastern Health, VIC; Karen Hall, Nurse Counsellor, Helpline, Cancer Council SA, and Clinical Nurse, Oncology/Haematology Inpatient Unit, Flinders Medical Centre, SA; Julie McGirr, Cancer Helpline Nurse, Cancer Council Victoria, VIC; and Jodie Turpin, Consumer.