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. They 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 just below the rib cage, toward the middle 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 are then sent as urine to the bladder through thin tubes (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 1 tumor in 1 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 healthcare provider called a pathologist identifies these types by looking at the cancer cells under a microscope. The types of RCC include:
Clear cell. This is the most common type of RCC. The cancer cells look pale or clear.
Papillary. This is the second most common type of RCC. This type of tumor has tiny fingerlike growths.
Chromophobe. This is a rare form of RCC. The cells are larger than other types of RCC.
Collecting duct. This is also a rare form of RCC. The cancer cells look like irregular tubes.
Unclassified. This includes tumors that have cells from more than 1 type of cancer. It also includes tumors with cells that don’t fit into the other categories.
Other types of kidney cancer
Other less-common types of kidney cancers include:
Transitional cell carcinoma. This is also known as urothelial carcinoma. It starts where the ureter and kidney meet. This area is called the renal pelvis. This type of kidney cancer can act and look like bladder cancer.
Wilms tumor. This cancer most always occurs in children. It’s very rare in adults.
Renal sarcoma. This is a very rare type of kidney cancer. It begins in the blood vessels and connective tissue around the kidneys.
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 often 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.
Kidney Cancer: Risk Factors
What is a risk factor?
A risk factor is anything that may increase your chance of having a disease. Risk factors for a certain type of cancer might include smoking, diet, family history, or many other things. The exact cause of someone’s cancer may not be known. But risk factors can make it more likely for a person to have cancer.
Things you should know about risk factors for cancer:
Risk factors can increase a person’s risk, but they don’t always cause the disease.
Some people with 1 or more risk factors never develop cancer. Other people with cancer have no known risk factors.
Some risk factors are very well known. But there’s ongoing research about risk factors for many kinds of cancer.
Some risk factors, such as family history, may not be in your control. But others may be things you can change. Knowing the risk factors can help you make choices that might help lower your risk. For instance, if an unhealthy diet is a risk factor, you may choose to eat healthy foods. If excess weight is a risk factor, your healthcare provider may help you lose weight.
Who is at risk for kidney cancer?
Risk factors for kidney cancer include:
Age. Most people with kidney cancer are age 55 and older. The risk increases with age, but this cancer can happen at any age. It can also affect children and young adults.
Gender. Men are more likely than women to develop kidney cancer. This may be because men are more likely to smoke and work with cancer-causing chemicals.
Race. African Americans are at a slightly higher risk for kidney cancer.
Smoking. The longer you’ve smoked, the greater your chance of having kidney cancer.
Obesity. People who are very overweight are more likely to get kidney cancer than those at a healthy weight.
Medicines. Kidney cancer has been linked to using certain medicines for a long time. These include water pills (diuretics) and over-the-counter pain medicines, like acetaminophen, aspirin, and ibuprofen.
Contact with chemicals. Contact with certain substances puts you at higher risk for kidney cancer. This includes chemicals and substances like the metal cadmium (in batteries, paint, and welding materials), herbicides, and organic solvents, especially trichloroethylene.
High blood pressure. People with high blood pressure have a higher risk for kidney cancer. It’s not known if the risk is because of the condition, the medicines used to treat it, or both.
Advanced or chronic kidney disease. This puts you at a higher risk for kidney cancer. People getting dialysis are at an even higher risk.
Certain inherited conditions. Certain syndromes linked to genes passed in families affect your kidney cancer risk. For instance, people who have von Hippel-Lindau (VHL) disease are at higher risk for kidney cancer. Other conditions linked to kidney cancer include Birt-Hogg-Dube syndrome, hereditary papillary renal cell carcinoma, Cowden syndrome, and hereditary leiomyomatosis.
Family history of kidney cancer. People with a family history of kidney cancer have a higher chance of developing the disease. This risk is highest in brothers or sisters of those with the cancer.
What are your risk factors?
Talk with your healthcare provider about your risk factors for kidney cancer. If you have a family history of kidney cancer or other disorders linked with the disease, you may want to ask about genetic testing and kidney cancer screening. (Screening means looking for cancer in people who don’t have symptoms.)
If genetic tests show a risk for kidney cancer, your healthcare provider may advise you get screened often for kidney cancer. There are no standard guidelines for how often you should be screened or what tests to use if you are at increased risk. Your healthcare provider will advise a screening schedule based on your overall health and risk factors.