The two kidneys lie to the sides of the upper part of the tummy (abdomen), behind the intestines, and either side of the spine. Each kidney is about the size of a large orange, but bean-shaped.
A large renal artery takes blood to each kidney. The artery divides into many tiny blood vessels (capillaries) throughout the kidney. Tiny structures in the kidneys, called nephrons, filter the blood contained in the capillaries. Water and waste materials which filter through the walls of the capillaries into the nephrons form urine.
Urine passes along thin channels (tubules) which are part of each nephron, into larger channels (ducts) which drain the urine into the inner part of the kidney (the renal pelvis).
Urine passes down a tube called a ureter which goes from each kidney to the bladder. Urine is stored in the bladder until it is passed out through the tube called the urethra when we go to the toilet. The cleaned (filtered) blood from each kidney collects into a large renal vein which takes the blood back towards the heart.
Some specialised cells in the kidneys also make some hormones, including:
- Renin - which helps to regulate blood pressure.
- Erythropoietin - which helps to stimulate the bone marrow to make red blood cells.
- Calcitriol - which helps to regulate the calcium level in the blood.
Although it is normal to have two kidneys, we can live perfectly well with just one healthy kidney.
WHAT IS THE KIDNEY CANCER?
Cancer is when cells in the body grow out of control. These cells can form a tumor or damaged tissue. If cancer cells grow in the kidney, it is called kidney cancer.
- The most common kidney cancer in adults is renal cell carcinoma. It forms in the lining of very small tubes in the kidney.
- Cancers found in the center of the kidney are known as transitional cell carcinoma.
- Wilms tumor is a kidney cancer that very young children can get.
On average, people are diagnosed with kidney cancer at around age 64. It’s rarely found in people younger than age 45. Generally, our lifetime risk for developing cancer in the kidney is about 1 in 63 (1.6%)1. This risk is higher in men than in women.
With timely diagnosis and treatment, kidney cancer can be cured. To learn more about symptoms, diagnosis, treatment options and common questions, read on.
BASIC FACTS ABOUT KIDNEY CANCER
The terms "tumor," "mass," or "lesion" are used to describe an abnormal growth in the kidney. Tumors can be benign (non-cancerous) or malignant (cancerous). A fluid-filled sac, called a cyst, is the most common growth found in a kidney. Cysts are mostly not cancerous. Solid kidney tumors can be benign, but most often are found to be cancer.
Kidney cancer is one of the top 10 most common cancers diagnosed in the United States. In 2017, about 63,990 people will be diagnosed. About 14,000 people will die from this disease. Of the people who are diagnosed early (stage I or II cancer), 75-80% will survive.
WHAT ARE THE SYMPTOMS OF KIDNEY CANCER?
Many people with kidney cancer have no symptoms at first, especially when the cancer is small. As the cancer develops, the following may occur.
1. Blood in urine
In many cases, the first symptom is to pass blood in the urine (haematuria), which is usually painless. The blood in the urine may come and go as the tumour bleeds from time to time. (There are many causes of blood in the urine apart from cancer, such as bladder or kidney infections, inflammation of the kidney, kidney stones, etc. You should always report this symptom to your doctor, even if it goes, to clarify the cause of the bleeding.)
2. Other symptoms
Various other symptoms may occur, typically as the tumour becomes larger. They include:
- Pain or discomfort in the side or back of the abdomen (loin pain).
- High temperatures (fevers) and sweats.
- A swelling in the area over a kidney.
- Anaemia, which can cause tiredness. You may also look pale.
- Some renal cell tumours produce abnormal amounts of certain hormones. This can lead to problems such as: 1). A high blood calcium level which can cause various symptoms, such as increased thirst, feeling sick, tiredness, and constipation. 2). Too many red blood cells being made (polycythaemia). 3). High blood pressure (hypertension).
HOW IS KIDNEY CANCER DIAGNOSED AND ASSESSED?
A doctor may suspect that you have kidney cancer from the symptoms and signs listed above and then arrange tests to confirm the diagnosis. However, in developed countries, about half of kidney cancers are diagnosed before any symptoms develop. They are usually seen by chance when a scan or other investigation is done for another reason.
1. Test To Confirm The Diagnosis
An ultrasound scan of the kidney can usually detect a kidney cancer. This is often one of the first tests done if your doctor suspects that you may have kidney cancer. An ultrasound scan is a safe and painless test which uses sound waves to create images of organs and structures inside your body. See separate leaflet called Ultrasound Scan for more details. A more sophisticated scan called a computerised tomography (CT) scan may be used if there is doubt about the diagnosis.
2. Assessing The Extent And Spread
If you are found to have a kidney cancer then other tests are likely to be advised. These may include one or more of: a CT scan or magnetic resonance imaging (MRI) scan of the abdomen and chest, a chest X-ray, kidney function blood tests and sometimes other tests. This assessment is called staging of the cancer.
The aim of staging is to find out:
- How much the tumour in the kidney has grown and whether it has grown to the edge, or through the outer part of the kidney.
- Whether the cancer has spread to local lymph glands (nodes).
- Whether the cancer has spread to other areas of the body (metastasised).