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Kidney (Renal) Cancer: Introduction

What is cancer?

Cancer is when cells in the body change and grow out of control. To help you understand what happens when you have cancer, let’s look at how your body works normally. Your body is made up of tiny building blocks called cells. Normal cells grow when your body needs them, and die when your body does not need them any longer.

Cancer is made up of abnormal cells that grow even though your body doesn’t need them. In most cancers, the abnormal cells grow to form a lump or mass called a tumor. If cancer cells are in the body long enough, they can grow into (invade) nearby areas. They can even spread to other parts of the body (metastasis).

What is kidney cancer?

Cancer that starts in kidney cells is called kidney or renal cancer.

Understanding the kidneys

The kidneys are 2 bean-shaped organs. Each is about the size of a bar of soap. They sit in the body towards the middle to lower part of the back. There is 1 kidney on each side of the spine. The kidneys help filter waste and excess fluid from the blood. The liquid and waste is then sent as urine to the bladder through thin tubes called ureters. Urine then leaves the body through a tube called the urethra. The kidneys also help control blood pressure. And they help make sure there are enough red blood cells in the body.

When kidney cancer forms

A kidney is made up of many layers of cells. Kidney cancer can affect any one or all of these layers. The cancer can stop the kidneys from working normally. Kidney cancer may spread to other parts of the body. When cancer spreads, it’s called metastasis. The more cancer spreads (metastasizes), the harder it is to treat.

What are the different types of kidney cancer?

The main type of kidney cancer is called renal cell carcinoma (RCC). About 9 out of 10 kidney cancer tumors are this type. If you have this type of kidney cancer, you may have more than one tumor in one or both kidneys. These may be large by the time they are diagnosed. But most cases of kidney cancer are found before the cancer has spread to other organs.

There are different types of RCC. A health care provider called a pathologist identifies these types by looking at the cancer cells under a microscope. The types of RCC include:

Other types of kidney cancer

Other less-common types of kidney cancers include:

Kidney tumors that aren’t cancer

There are several types of kidney tumors that are not cancer (benign). These include renal cell adenoma, renal oncocytoma, and angiomyolipoma. These types of tumors may still affect kidney function and can cause pain and other symptoms. But the cells usually do not spread to other organs.

Talk with your healthcare provider

If you have questions about kidney cancer, talk with your healthcare provider. Your healthcare provider can help you understand more about this cancer.