The primary function of the kidney is to filter waste from our blood. About 50 gallons of blood enter our kidneys every day. They also process approximately two quarts of extra water and waste products. The waste and extra water is turned into urine. The urine then travels down tubes, called ureters, and is stored in the bladder until excretion (urination).
Like other organs in our bodies, the kidneys are vulnerable to infection and disease, including cancer. There are several types of cancer that can develop in the kidney, but renal cell carcinoma is by far the most prevalent. It is estimated that 9 of 10 cases of kidney cancer are renal cell carcinomas. Other types of kidney cancer, although much less commonly, include:
transitional cell carcinoma
- renal sarcoma
Causes and Risk Factors of Kidney CancerWe cannot pinpoint what exactly causes kidney cancer, but researchers have identified several risk factors for the disease. Causes and risk factors vary for each type of kidney cancer. Risk factors of kidney cancer may include:
workplace exposure to asbestos, benzene, cadmium,
- having Von Hippel-Lindau disease or hereditary papillary RCC (genetic conditions that increase the risk of kidney cancer)
- chronic kidney failure
Symptoms of Kidney CancerUnfortunately, kidney cancer symptoms usually do not appear until the disease has progressed. In fact, kidney cancer is usually detected "accidentally" when another symptom or condition is being investigated. Like with kidney cancer risk factors, symptoms vary based on the type of kidney cancer. There are some common symptoms, however. Symptoms of kidney cancer include:
- blood in the urine, either seen after urination or microscopically
- abdominal mass
- pain felt on the side or or lower back
Diagnosing Kidney CancerA palpable mass or the finding of a mass on an x-ray done for another reason are usually what leads a physician to suspect kidney cancer. The first step in diagnosing kidney cancer is through various imaging tests. Ultrasound, CT scan, MRI, and intravenous pyelogram (IVP) are all methods that may be used to help diagnose kidney cancer.
Ultimately, it is a kidney biopsy that will confirm the presence or absence of cancer and what type it is. A kidney biopsy can be done through a fine needle aspiration biopsy technique.
If cancer is found, more tests may need to be done to determine if the kidney cancer has spread to nearby tissues and organs. This is called staging.
Treatment of Kidney CancerJust about everyone with kidney cancer will receive some type of surgery to treat their cancer. People with early-stage kidney cancer are the best candidates for surgery, but those who have a later stage of kidney cancer may not be healthy enough to withstand surgery.
Chemotherapy and radiation therapy may be used to treat kidney cancer, but are often ineffective. Some tumors just don't respond well like other types of cancer. Radiation therapy is most often used palliatively, to relieve discomfort caused by the effects of the cancer spreading.
Immunotherapy, also called biologic therapy, is a treatment option for many types of kidney caner. Immunotherapy drugs stimulate the immune system to help fight cancer. Common immunotherapy drugs used to treat kidney cancer include interferon or interleukin-2.
Several targeted therapy drugs have been approved for use in some people with kidney cancer. These kind of drugs block and prevent the growth and spreading of malignant cells. They do this by attacking the cells directly or preventing the growth of blood vessels that provide tumors nourishment to grow. Approved targeted therapy drugs include:
Prevention of Kidney CancerWhile there are no proven kidney cancer prevention methods, there are steps we can take to reduce our risk of kidney cancer.
Quit Smoking or Don't Start. Smoking is a strong risk factor for renal cell carcinoma. As soon as you quit (it's never too late!), your body reaps the benefits of being tobacco free. Quitting smoking is the best defense against lung cancer. Need help kicking the habit? Visit the About.com Smoking Cessation site.
Know What You are Being Exposed to in the Workplace. If you are exposed to fumes, dust and chemicals in the workplace, you have a right to know what you are being exposed to. Gasoline, diesel exhaust, arsenic, beryllium, vinyl chloride, nickel chromates, coal products, mustard gas and chloromethyl ethers are all carcinogens and can be found in some work environments. Talk to your employer about limiting your exposure.
Eat a Well-Balanced Diet. Eating a well-balanced diet is advantageous for many reasons. A diet rich in fruits and vegetables, but low in animal fats and salt, is beneficial. Obesity is a risk factor many types of kidney cancer.
American Cancer Society. "What is Kidney Cancer". Detailed Guide: Kidney cancer. 06 Nov 2007. Accessed July 28, 2008.
American Cancer Society. "How is Kidney Cancer Treated?". Detailed Guide: Kidney Cancer. 06 Nov 2007. Accessed July 28, 2008.