Kidney cancer is a disease in which cancer cells grow in the kidneys. The kidneys are two bean-shaped organs, located just above the waist, on each side of the spine. Their main function is to filter the blood and produce urine by which the body rids itself of waste products and excess water.

Cancer occurs when cells in the body (in this case kidney cells) divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms, called a growth or tumor. The term cancer refers to malignant tumors, which can invade nearby tissues and spread to other parts of the body. A benign tumor does not invade or spread.

There are two main types of kidney cancer: Wilms’ tumor, which occurs predominantly in children, and renal cell carcinoma in adults. The cells that line the ureter may also give rise to transitional cell cancer, and the connective tissues of the kidney may produce sarcomas, which are rare.

Causes

The cause of kidney cancer is unknown.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors for kidney cancer include:

• Smoking

• Family history of certain hereditary forms of kidney cancer

• Age: 50 or older

• Sex: Male

• Certain occupational exposures (eg, asbestos and aniline) and tanning products

• Exposure to some toxins, such as astrolachia (an herb common in some Chinese herbal preparations)

• Balkan nephritis

• Chromic renal stones

• Phenacitin abuse

• Tuberous sclerosis (a hereditary condition that causes tumors to grow in many different organs, including the kidney)

• Dialysis treatment

Symptoms

Symptoms may include:

• Blood in the urine

• Unexplained lower back pain or new pain elsewhere

• Shortness of breath or cough

• Lump in the belly

• Elevated blood pressure

• Unplanned, significant weight loss

• Unexplained fever

• Swelling of ankles, legs, and/or abdomen

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam.

Tests may include:

Blood and Urine Tests–to check kidney function or find substances that indicate kidney cancer may be present.

Bone Scan–a test where you receive a special radioactive material that specifically lights up bones that are undergoing an active process (such as tumor growth). Kidney cancer likes to spread to the bones and this test is often performed to ensure the bones are not involved by the cancer.

X-rays of the Chest and Abdomen–a test that uses radiation to take pictures of structures inside the body.

Intravenous Pyelogram–an x-ray of the kidneys and ureters after injection of contrast dye into the blood.

Renal Angiography–an x-ray of arteries that are leading to a possible kidney tumor.

CT Scan–a type of x-ray that uses a computer to make pictures of the inside of the kidneys and their surroundings.

MRI Scan–a test that uses magnetic waves to make pictures of the inside of the kidneys and their surroundings.

Renal Ultrasound–a test that uses sound waves to examine the kidneys.

Laparoscopy–a thin, lighted tube inserted through a small incision in the abdomen to look at the kidney.

Cytoscopy–examination of the bladder, ureters, and kidneys via a thin tube inserted through the urethra.

Biopsy–removal of a sample of kidney tissue to test for cancer cells.

Treatment

Once kidney cancer is found, staging tests are performed to find out if the cancer has spread and, if so, to what extent. Treatment depends on the stage.

Surgery is the most important component of any curative approach to kidney cancer. Chemotherapy is rarely given because generally there is no benefit. There is some information suggesting immunotherapies (interleukin or interferon) may be of some benefit, though the response to these agents is generally quite low and unreliable. Radiation is effective for kidney cancer that has spread to the lung, bones, or brain but is not considered curative.

Surgery–surgical removal of a cancerous tumor and nearby tissues, and possibly nearby lymph nodes. Surgeries to treat kidney cancer include:

Radical Nephrectomy–removal of the entire kidney, adrenal gland, and nearby fatty tissue and lymph nodes.

Partial Nephrectomy–removal of the cancerous part of the kidney only. Used to treat smaller tumors that have not spread locally.

Removal of Metastases–removal of cancerous tissues that have spread to other parts of the body, particularly if they are causing symptoms.

Radiation Therapy (or Radiotherapy)–the use of radiation to kill cancer cells and shrink tumors. Radiation may be:

External Radiation Therapy–radiation directed at the tumor from a source outside the body

Chemotherapy–the use of drugs to kill cancer cells. Chemotherapy may be given in many forms including: pill, injection, and via a catheter. The drugs enter the bloodstream and travel through the body killing mostly cancer cells, but also some healthy cells.

Immunotherapy–the use of drugs like interleukin-2 and interferon to help the immune system to better fight and destroy cancer cells.

Prevention

Measures to prevent kidney cancer are limited:

• Avoid using tobacco products

• Avoid occupational exposures

See your doctor at the first sign of possible symptoms, since early detection is the key to cure.

RESOURCES:

American Cancer Society
http://www.cancer.org

American Urological Association Foundation
http://www.afud.org

The Kidney Cancer Association
http://www.nkca.org

References:

American Cancer Society website. Available at: http://www.cancer.org.

The Merck Manual of Medical Information, Simon and Schuster;2000.

National Cancer Institute website. Available at: http://www.cancer.gov/.