The kidneys are two bean-shaped organs, each about the size of a fist. They are deep inside your abdomen, positioned near the middle of your back, on either side of the spine.
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
The kidneys are part of the body's urinary system. When they 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.
The main function of the kidneys is to cleanse the blood, but they also help your body control how much blood it needs. They do this by making hormones that help regulate blood pressure and trigger the production of red blood cells.
An adrenal gland sits above each 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.
What is the main type of kidney cancer?
Kidney cancer is cancer that starts in the cells of the kidney.
About 9 out of 10 kidney cancers are renal cell carcinoma (RCC), sometimes called renal adenocarcinoma. RCCs start in the cells lining small tubes in the kidney's nephrons. The information in this section is about RCC.
In the early stages of RCC the primary cancer forms a tumour that is confined to the kidney. Usually only a single kidney is affected, but in rare cases both kidneys can be affected. As the cancer grows, it can spread to areas near the kidney, such as the surrounding fatty tissue, veins, adrenal glands, ureters or the liver. It may also spread to other parts of the body, such as the lungs or bones.
Types of renal cell carcinoma (RCC)
There are several types of RCC, based on the way the cells look under a microscope. The most common type is clear cell renal cell carcinoma.
Clear cell RCC
- makes up about 75% of RCC cases
- cancer cells look empty or clear
- makes up about 10–15% of RCC cases
- cancer cells are arranged in finger-like fronds
- makes up about 5% of RCC cases
- cancer cells are large and pale
Other types of RCC
- include renal medullary carcinoma, collecting duct carcinoma, MiT family translocation RCC, sarcomatoid RCC and other very rare types
- together make up about 5–10% of RCC cases
Are there other types?
RCC is the most common type of kidney cancer, but there are other less common types:
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. See Understanding Bladder Cancer.
Wilms tumour (nephroblastoma)
This is the most common type of kidney cancer in younger children, but it is still rare. Visit childrenscancer.canceraustralia.gov.au.
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. See the Cancer Council information on the primary cancer.
How common is kidney cancer?
More than 3000 people are diagnosed with kidney cancer in Australia each year. It makes up about 2.5% of all cancers. It is twice as common in men than women, and is the ninth most diagnosed cancer for Australian men. The risk of kidney cancer increases with age, and most cases occur in people over 50. 1
What are the symptoms?
Most people with kidney cancer have no symptoms and many are diagnosed with the disease when they see a doctor for an unrelated reason. Symptoms can, however, include:
- blood in the urine (haematuria) – this may be obvious
- or the urine may just look dark, rusty or brown
- pain in the lower back or side not caused by injury
- a lump in the abdomen
- constant tiredness
- unexplained weight loss
- fever (not caused by a cold or flu).
Cancer can affect the amount of hormones produced by the kidneys, and this may lead to a low red blood cell count (anaemia), a high red blood cell count (polycythaemia) or high levels of calcium in the blood (hypercalcaemia). Sometimes these problems can cause symptoms such as fatigue, dizziness, headaches, constipation, abdominal pain, and depression.
The symptoms listed above can also occur with other illnesses, so they don'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).
"Kidney cancer can be a silent cancer until it is quite advanced, so I do feel thankful that it was discovered incidentally, when it was small and easier to treat." - Chris
What are the risk factors?
The factors listed below may increase the risk of a person developing kidney cancer. However, having one or more of these risk factors does not mean you will develop cancer.
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.
Excess body fat may cause changes in certain hormones that can lead to kidney cancer.
High blood pressure
Whatever the cause, high blood pressure increases the risk of kidney cancer.
People with end-stage kidney disease have a higher risk of developing kidney cancer.
People who have family members with kidney cancer, especially a sister or brother, are at increased risk.
About 2–3% of kidney cancers occur in people who have particular inherited syndromes, including von Hippel-Lindau disease, hereditary papillary RCC and BirtHogg-DubÈ 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.
Which health professionals will I see?
Your GP will arrange the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to a specialist such as a urologist. The specialist will arrange further tests. If kidney cancer is diagnosed, the specialist will consider treatment options. Often these will be discussed with other health professionals at what is known as a multidisciplinary team (MDT) meeting. During and after treatment, you will see a range of health professionals who specialise in different aspects of your care.
|MDT health professionals
||assists you with treatment decisions and works in partnership with your specialists in providing ongoing care
||treats diseases of the male and female urinary systems, and the male reproductive system; performs surgery
||diagnoses and treats conditions that cause kidney (renal) failure or impairment; may be consulted by your urologist when planning surgery
||treats cancer with drug therapies such as chemotherapy, targeted therapy and immunotherapy (systemic treatment)
||treats cancer by prescribing and coordinating a course of radiation therapy
||analyses x-rays and scans; an interventional radiologist may also perform a biopsy under ultrasound or CT, and deliver some treatments
|cancer care coordinator
||coordinates your care, liaises with other members of the team, and supports you and your family throughout treatment; care may also be coordinated by a clinical nurse consultant (CNC) or clinical nurse specialist (CNS)
||administers drugs and provides care, information and support throughout treatment
|physiotherapist, occupational therapist
||assist with physical and practical problems, including restoring movement and mobility after treatment and recommending aids and equipment
||recommends an eating plan to follow while you are in treatment and recovery
||links you to support services and helps you with emotional, practical or financial issues
|psychiatrist*, psychologist, counsellor
||help you manage your emotional response to diagnosis and treatment
Expert content reviewers:
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.
1. Australian Institute of Health and Welfare (AIHW), Australian Cancer Incidence and Mortality (ACIM) books: kidney cancer, AIHW, Canberra, December 2017.