Frequently Asked Questions About Kidney Cancer

Listed below are some frequently asked questions about kidney cancer.

Q: What are the kidneys, and what do they do?

A: The kidneys are two bean-shaped organs, each about the size of a fist. You have one on either side of your spine in the middle of your back. They have three main roles:

  • Filter waste from the blood and make urine

  • Make the hormone erythropoietin that controls the production of red blood cells in the bone marrow

  • Help regulate blood pressure

While most people are born with two kidneys, it is possible to survive with one, or none. People with no kidneys or with kidneys that do not work right survive with the help of dialysis. With dialysis, a special machine does the kidneys' job of filtering the blood.

Q: What is kidney cancer?

A: This is cancer that starts in the kidney. The most common type of kidney cancer is called renal cell carcinoma (RCC). The term renalis derived from the Latin word for kidney. About 90 percent of all kidney cancers are renal cell carcinomas. The other 10 percent are made up of transitional cell carcinomas, Wilms' tumors (found in children), and other rare tumors.

Q: Are there different types of renal cell carcinoma?

A: These are the five main types of renal cell carcinoma (RCC). A pathologist can identify them under a microscope based on how they look:

  • Clear cell, which is the most common type of RCC

  • Papillary, which is the second most common type

  • Chromophobe

  • Collecting duct

  • Unclassified

Q: Who gets kidney cancer?

A: About 58,000 people in the United States are told they have kidney cancer each year. Men get kidney cancer more often than women. People who smoke have almost twice the risk of getting kidney cancer as nonsmokers. Here are some other risk factors:

  • Von Hippel-Lindau (VHL) disease

  • Family history of kidney cancer

  • Obesity

  • Exposure to workplace chemicals such as cadmium, benzene, and asbestos

However, many people with kidney cancer have no known risk factors. On the other hand, people who have one or more of known risk factors may never get the disease.

Q: What are the symptoms of kidney cancer?

A: In the early stages, kidney cancer often causes no symptoms. As the cancer grows, symptoms may develop. These are the most common symptoms in people with kidney cancer:

  • Blood in the urine

  • Side or back pain

  • A mass or lump in the side or lower back

  • Fatigue, which is a chronic, unexplained tiredness

  • Rapid weight loss without making an effort to lose weight

  • Other symptoms, such as fever with no known cause, leg or ankle swelling, and high blood pressure

People with renal cancer may have any combination of these symptoms. If you have any of these symptoms, see a doctor as soon as possible.

Q: How is kidney cancer diagnosed?

A: If a doctor thinks a person has kidney cancer, there are many ways to find out for sure. These are the tests a doctor may do, and they are usually done in about this order:

  • Medical history and physical exam. The doctor asks all about the person's medical history. He or she also asks about the person's family history of kidney cancer and other conditions that may be related to kidney cancer. This includes assessing any risk factors. The doctor will also do an exam.

  • Urinalysis. For this test, the person collects a small amount of his or her urine. Then, it is tested to see if blood, protein, or bacteria is present. The doctor may do a special urine test called urine cytology. This test checks for cancer cells in the urine. 

  • Blood tests. A complete set of blood tests is usually done when a doctor suspects kidney cancer. There is no specific blood test that can diagnose kidney cancer, but tests can show problems associated with kidney cancer.

  • Imaging tests. These are some of the tests used to take pictures of the inside of a person's body:

  • Biopsy. During a biopsy, the doctor removes a small amount of the tumor. A pathologist then examines this sample under a microscope. For kidney cancer, the type of biopsy used is called fine needle aspiration (FNA). In most cases of suspected kidney cancer, no biopsy is taken. When a CT scan or an MRI suggests kidney cancer, people usually go directly to surgery to have the tumor and maybe the entire kidney removed. The pathologist examines the specimen removed during surgery to confirm the diagnosis.

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