Types of Cancer : Kidney Cancer

Definition

Your kidneys are two bean-shaped organs, each about the size of your fist. They're located behind your abdominal organs, one on each side of your spine. Like other major organs in the body, the kidneys can sometimes develop cancer.

In adults, the most common type of kidney cancer is renal cell carcinoma, which begins in the cells that line the small tubes within your kidneys. Children are more likely to develop a kind of kidney cancer called Wilms' tumor.

The American Cancer Society estimates that almost 51,000 people in the United States are diagnosed with kidney cancer each year. The incidence of kidney cancer seems to be increasing, though it isn't clear why. Many kidney cancers are detected during procedures for other diseases or conditions. Imaging techniques, such as computerized tomography (CT), are being used more often, which may help find more kidney cancers.

Symptoms

Kidney cancer rarely causes signs or symptoms in its early stages. In the later stages, kidney cancer signs and symptoms may include:

• Blood in your urine, which may appear pink, red or cola-colored
• Back pain just below the ribs that doesn't go away
• Weight loss
• Fatigue
• Intermittent fever

Causes

Your kidneys are part of the urinary system, which removes waste and excess fluid and electrolytes from your blood, controls the production of red blood cells, and regulates your blood pressure. Inside each kidney are more than a million small filtering units called nephrons. As blood circulates through your kidneys, the nephrons filter out waste products as well as unneeded minerals and water. This liquid waste — urine — flows through two narrow tubes (ureters) into your bladder, where it's stored until it's eliminated from your body through another tube, the urethra.

Just what causes kidney cells to become cancerous isn't clear. But researchers have identified certain factors that appear to increase the risk of kidney cancer.

Types of kidney cancer
The most common types of kidney cancer include:

• Renal cell carcinoma. This type of kidney cancer usually begins in the cells that line the small tubes of each nephron. In most cases, renal cell tumors grow as a single mass, but you may have more than one tumor in a kidney or develop tumors in both kidneys.
• Transitional cell carcinoma. This type of kidney cancer develops in the tissue that forms the tubes that connect the kidneys to the bladder. Transitional cell carcinomas can also begin in the ureters themselves or in the bladder.
• Wilms' tumor. Wilms' tumor is a type of kidney cancer that occurs in young children.

Risk factors

Renal cell carcinoma risk factors
The majority of kidney cancers are renal cell carcinomas. Risk factors for renal cell carcinoma include:

• Age. Your risk of renal cell carcinoma increases as you age. Renal cell carcinoma occurs most commonly in people 60 and older.
• Sex. Men are more likely to develop renal cell carcinoma than women are.
• Smoking. Smokers have a greater risk of renal cell carcinoma than nonsmokers do. The risk increases the longer you smoke and decreases after you quit.
• Obesity. People who are obese have a higher risk of renal cell carcinoma than do people who are considered average weight.
• High blood pressure (hypertension). High blood pressure increases your risk of renal cell carcinoma, but it isn't clear why. Some research in animals has linked high blood pressure medications to an increased risk of kidney cancer, but studies in people have had conflicting results.
• Chemicals in your workplace. Workers who are exposed to certain chemicals on the job may have a higher risk of renal cell carcinoma. People who work with chemicals such as asbestos, cadmium and trichloroethylene may have an increased risk of kidney cancer.
• Treatment for kidney failure. People who receive long-term dialysis to treat chronic kidney failure have a greater risk of developing kidney cancer. People who have a kidney transplant and receive immunosuppressant drugs also are more likely to develop kidney cancer.
• Von Hippel-Lindau disease. People with this inherited disorder are likely to develop several kinds of tumors, including, in some cases, renal cell carcinoma.
• Hereditary papillary renal cell carcinoma. Having this inherited condition makes it more likely you'll develop one or more renal cell carcinomas.

Transitional cell carcinoma risk factors
Risk factors for transitional cell carcinoma include:

• Smoking. Smoking increases your risk of transitional cell carcinomas.
• Chemicals in your workplace. Working with certain chemicals may increase your risk of transitional cell carcinoma.
• A withdrawn medication. Phenacetin, which was removed from the market in the United States in the early 1980s, has been linked to kidney cancer. Phenacetin was used in prescription and over-the-counter pain relievers.

When to seek medical advice

See your doctor right away if you notice blood in your urine. In most cases, this doesn't mean you have kidney cancer. Blood in the urine may be a sign of many other conditions.

Tests and diagnosis

A kidney cancer diagnosis typically begins with a complete medical history and a physical exam. Your doctor may also recommend blood and urine tests. If your doctor suspects a problem or if you're at high risk of kidney cancer, you may also have one or more of the following tests to check your kidneys for growths or tumors:

• Ultrasound. An ultrasound uses high-frequency sound waves to generate images of your internal organs, such as your kidneys and bladder, on a computer screen.
• Computerized tomography (CT) or magnetic resonance imaging (MRI) scan. CT scans use computers to create more-detailed images than those produced by conventional X-rays. MRI scans use magnetic fields and radio waves to generate cross-sectional pictures of your body.

• Tissue sample (biopsy). In selected cases, your doctor may recommend a procedure to remove a small sample of cells (biopsy) from a suspicious area of your kidney. During a biopsy, a surgeon uses ultrasound or CT images to guide a long, thin needle into your kidney to remove the cells. The cells are then examined under a microscope to determine whether they are cancer.

  Biopsy procedures have risks, such as infection, bleeding and a very small chance that cancer could spread to the area where the needle is inserted. Because surgery is usually the first line treatment for kidney cancer, your doctor may forgo biopsy if he or she believes your tumor is very likely to be cancerous. That way you avoid the additional risks of a biopsy. Kidney biopsy is typically reserved for cases that are most likely to be noncancerous or for people who can't undergo an operation.

Additional tests for transitional cell cancer
Tests and procedures used to diagnose transitional cell kidney cancer may include:

• X-ray imaging of your urinary system (excretory urogram). X-rays of your urinary system may show signs of cancer. Your health care team will inject a dye into a vein in your arm. The dye is processed by your kidneys and your urinary system, and the dye makes it possible to see your urinary system on an X-ray.
• Looking inside your bladder (cystoscopy). Your doctor may use a long, narrow tube called a cystoscope to see the inside of your bladder. The cystoscope, which carries a light source and a special lens, is inserted through your urethra into your bladder. A cystoscope can also be used to extract a small tissue sample (biopsy) from any suspicious areas.

Kidney cancer staging
Once your doctor diagnoses kidney cancer, the next step is to determine the extent, or stage, of the cancer. Staging tests for kidney cancer may include additional CT scans, a chest X-ray or other imaging scans your doctor feels are appropriate.

Then your doctor assigns a number, called a stage, to your cancer. Kidney cancer stages include:

• I. Tumor is small and confined to the kidney
• II. Tumor is larger than a stage I tumor, and is confined to the kidney
• III. Tumor extends beyond the kidney to the surrounding tissue or the adrenal glands, and may also spread to a nearby lymph node
• IV. Cancer spreads outside the kidney or to distant parts of the body

Treatments and drugs

Together, you and your treatment team will discuss all of your kidney cancer treatment options. The best approach for you may depend on a number of factors, including your general health, the kind of kidney cancer you have, whether the cancer has spread and your own preferences for treatment.

Surgery
Surgery is the initial treatment for the majority of kidney cancers. Surgical procedures used to treat kidney cancer include:

• Removing the affected kidney (nephrectomy). Radical nephrectomy involves the removal of the kidney as well as the adrenal gland that sits atop the kidney, a border of healthy tissue and adjacent lymph nodes. Nephrectomy can be done through an incision, meaning the surgeon makes a large cut in your skin to access your kidney. Or nephrectomy can be done laparoscopically, using small incisions to insert a video camera and tiny surgical tools. The surgeon watches a video monitor in order to perform the nephrectomy.
• Removing the tumor from the kidney (nephron-sparing surgery). During this procedure, the surgeon removes the tumor, rather than the entire kidney. Nephron-sparing surgery may be an option if you have only one kidney or if you have an early-stage kidney cancer.

What type of surgery your doctor recommends will be based on your cancer and its stage, as well as your health and personal preferences. Surgery carries a risk of bleeding and infection.

Treatments when surgery isn't possible
For some people, surgery may be too risky. These people have other options for treating their kidney cancers, including:

• Blocking blood flow to the tumor (embolization). In this procedure, a special material is injected into the main blood vessel leading to the kidney. By clogging this vessel, the tumor is deprived of oxygen and other nutrients. Arterial embolization also may be used before an operation or to relieve pain and bleeding when an operation isn't possible. Side effects may include temporary nausea, vomiting or pain.
• Treatment to freeze cancer cells (cryoablation). Recent studies show cryoablation may be useful for treating kidney tumors that can't be removed through surgery. During cryoablation, one or more special needles (cryoprobes) are inserted through small incisions in your skin and into the tumor. Gas in the needles creates extreme cold that causes the cells around the point of each needle to freeze. Doctors use CT scans to monitor the procedure and to ensure that all of the visible cancer tissue and some of the surrounding healthy tissue is frozen. Another type of gas in the needles creates warmth to thaw the frozen tissue. Then the process is repeated. The cycles of freezing and thawing cause cancer cells to die. You may experience some pain after the procedure. Rare side effects may include bleeding, infection and damage to tissue surrounding the tumor.

Treatments for advanced and recurrent kidney cancer
Kidney cancer that recurs and kidney cancer that spreads to other parts of the body may be curable. In these situations, treatments may include:

• Surgery to remove as much of the kidney tumor as possible. Even when surgery can't remove all of your cancer, in some cases it may be helpful to remove as much of the cancer as possible.
• Drugs that use your immune system to fight cancer (biological therapy). Biological therapy (immunotherapy) uses your body's immune system to fight cancer. Drugs in this category include interferon and interleukin-2, which are synthetic versions of chemicals made in your body. These biological therapy drugs have serious side effects, including chills, fever, nausea, vomiting and loss of appetite. Biological therapy drugs are sometimes used alone, in combination or after surgery.
• Treatment that targets specific aspects of your cancer (targeted therapy). Targeted treatments block specific abnormal signals present in kidney cancer cells that allow them to proliferate. These drugs have shown promise in treating kidney cancer that has spread to other areas of the body. Two targeted drugs, sorafenib (Nexavar) and sunitinib (Sutent), block signals that play a role in the growth of blood vessels that provide nutrients to cancer cells and allow cancer cells to spread. Temsirolimus (Torisel), another targeted drug, blocks a signal that allows cancer cells to grow and survive. Targeted therapy drugs can cause side effects, such as a rash that can be severe, diarrhea and fatigue. Targeted drugs can also be very expensive, sometimes costing over $1,000 a treatment.
• Treatments for distant tumors. Kidney cancer cells that travel to other parts of the body (metastasize) can sometimes be treated. This depends on the number of distant tumors, their locations and your general health. Treatment options vary based on where your cancer has spread. Options might include surgery for brain metastasis or radiation for kidney cancer that has spread to bones.
• Clinical trials. Clinical trials are studies of new treatments and new techniques for treating kidney cancer and other diseases. Participating in a clinical trial may give you a chance to try the latest treatments, but it can't guarantee a cure. Discuss the available clinical trials with your doctor and carefully weigh the benefits and risks. Many kidney cancer clinical trials are studying new and existing targeted therapies to determine the best ways to use this new class of drugs.

Treatment for transitional cell cancer
Treatment for transitional cell cancer typically involves an extensive operation to remove the tumor, ureter, kidney and a portion of the bladder. Surgery to remove only the tumor may be an option in some cases.

Chemotherapy may be useful in treating transitional cell cancer that has spread or that recurs. Chemotherapy is a drug treatment that uses chemicals to kill quickly growing cells, such as cancer cells. Other rapidly growing cells, such as those in your gastrointestinal tract and your hair follicles, also are killed by chemotherapy drugs, which can cause side effects including nausea, vomiting and hair loss.

Prevention

Taking steps to improve your health may help reduce your risk of kidney cancer. To reduce your risk, try to:

• Quit smoking. If you smoke, quit. Many options for quitting exist, including support programs, medications and nicotine replacement products. Tell your doctor you want to quit and discuss your options together.
• Eat more fruits and vegetables. Add more fruits and vegetables to your diet. A variety of fruits and vegetables helps ensure that you're getting all the nutrients that your body needs. Replacing some of your snacks and side dishes with fruits and vegetables may help you lose weight.
• Exercise regularly. Aim for at least 30 minutes of exercise on most days. If you haven't been active before, get your doctor's permission. Start out slowly, and gradually increase the amount of time you exercise. Consider exercises such as walking or riding a bike.
• Maintain a healthy weight. Work to maintain a healthy weight. If you're overweight or obese, reduce the amount of calories you eat each day and try to exercise most days of the week. Ask your doctor about other healthy strategies to help you lose weight.
• Control high blood pressure. Ask your doctor to check your blood pressure at your next appointment. If your blood pressure is high, you can discuss options for lowering your numbers. Lifestyle measures, such as exercise, weight loss and diet changes, can help. Some people may need to add medications to lower their blood pressure. Discuss your options with your doctor.
• Reduce or avoid exposure to environmental toxins. If you work with toxic chemicals, take special precautions such as wearing a mask and heavy gloves. In the United States, your employer is required to tell you what chemicals you may be exposed to on the job. Follow your employer's safety procedures and ask your doctor if there are other ways to protect yourself from chemical exposure.