The Basics of Kidney Cancer (Renal Cell Carcinoma)

The kidneys are a pair of bean-shaped organs that lie on either side of the backbone. The kidneys have a number of important jobs. One of the biggest is filtering excess water, salt and wastes from the blood. They make urine from these waste products then send it to the bladder. The kidneys also produce a hormone that helps control blood pressure and the production of red blood cells.

What is kidney cancer?
Kidney cancer starts when cells in the kidneys start to grow in a disorderly fashion. Usually it starts as a single tumor in one of the kidneys. It often doesn't cause symptoms, so tumors may be large by the time they are found. The outlook for treatment is much better if the cancer is caught before it has spread to other organs (metastasized).

The most common type of kidney cancer is renal cell carcinoma. It accounts for about nine out of 10 cases of kidney cancer. It may also be called renal cell cancer or renal adenocarcinoma.

Kidney cancer occurs most often in older people. The average age at diagnosis is 65. It is rare in people younger than 40.

What are the symptoms?
In its early stages, kidney cancer usually causes no obvious symptoms. But as a kidney tumor grows, symptoms may occur. These may include:

• Blood in the urine (the most common symptom)
• A lump or mass in the side or belly

Other less common symptoms include:

• Fever
• Fatigue
• Loss of appetite
• Weight loss
• Side or back pain that doesn't go away

High blood pressure or anemia (a decrease in the number of red blood cells) may also be a sign of kidney cancer.

These symptoms may be caused by other conditions. See your doctor if you have any of these symptoms.