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How Does My Doctor Know I Have Kidney Cancer?

How Does My Doctor Know I Have Kidney Cancer?

Symptoms of kidney cancer can be caused by other less serious problems. To help rule out these other problems, your doctor will ask you questions about any symptoms, risk factors, and whether you have any family history of kidney disease in order to evaluate your medical history. The doctor then does a physical exam to look for signs of kidney cancer. He or she may check for fever and high blood pressure and feel your abdomen, sides, and back for tumors. These are usually the first steps in diagnosing cancer.

At this point, the doctor may order tests to see if you have cancer. Unlike most types of cancer, kidney cancer can often be diagnosed without a biopsy — a test that involves removing tissue so it can be examined under a microscope. You are likely to have more than one of these tests. You may have some of these tests:

Urinalysis

Nearly 50 percent of all people with kidney cancer have blood in their urine, which can be found from a urinalysis. This test is usually done as part of an overall general medical exam. In this test, you collect a small sample of your urine. It’s tested in a lab to see whether blood is present. Your doctor may do a special urine test, called urine cytology, to check for cancer cells in the urine as well.

Blood tests

Lab technician drawing blood from patient's arm

If kidney cancer is suspected, your doctor will probably do a complete set of blood tests. There is no specific blood test that can diagnose kidney cancer. However, a complete blood count and blood chemistry tests can reveal changes that are associated with kidney cancer. Here are some things your doctor may look for and talk with you about:

  • Too few red blood cells. This condition is called anemia, which occurs commonly in a number of different cancers. 

  • Too many red blood cells. Some types of kidney cancer cells make a hormone called erythropoietin, which causes bone marrow to make too many blood cells. This condition is called erythrocytosis or polycythemia.

  • A high blood calcium level. This may indicate that the cancer has begun to affect the bones, leading to more testing.  

  • A high level of proteins. Proteins are released by the liver.

Intravenous pyelogram (IVP)

This test uses a special dye and X-rays to examine the kidneys, ureters, and bladder. During this test, your doctor injects dye into one of your veins. X-rays are taken as the dye passes through your urinary tract. With the help of the dye, your doctor can spot abnormalities that may be caused by kidney cancer. 

Angiography

Angiography is very much like an IVP. It uses dye and X-rays to look at the kidneys. With angiography, the dye is injected directly into an artery going to your kidney. The test helps outline the blood vessels and lets doctors see whether blood vessels are feeding tumors. This test can also give doctors a better idea of whether the tumor can be taken out by surgery.

CT scan

A CT scan is a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. In many cases, this test can confirm a diagnosis of kidney cancer. If this test is done first, an IVP may not be needed.

To have the test, you lie still on a table as it gradually slides through the center of the CT scanner. Then the scanner directs a continuous beam of X-rays at your body. A computer uses the data from the X-rays to create many pictures, which can be used together to create a two-dimensional picture. A CT scan is painless. You may be asked to hold your breath one or more times during the scan. In some cases, you will be asked to drink a contrast dye four to six hours before the scan. Then you may be asked not to eat anything until a second set of pictures is taken. The dye allows your doctor to see certain tissues more clearly. The substance will gradually pass through your system and exit through your bowel movements. Dye may be given by vein as well to help produce even better pictures. Some people have a flushing reaction or other symptoms after the injection of dye. Be sure to tell your doctor if you have ever had a reaction to contrast dye, such as flushing, hives, or trouble breathing in the past. Special medications can be given beforehand to help prevent such a reaction. 

Magnetic resonance imaging (MRI)

This test gives doctors detailed information about blood vessels and muscle tissue. It may be used if the results of an X-ray or CT scan aren’t entirely clear. Or your doctor may use an MRI instead of a CT scan to confirm a diagnosis of kidney cancer if you are allergic to iodine, which is used in the contrast solution for CT scans.

MRIs are often used to determine if cancer has spread to your spine or brain. Instead of X-rays, MRIs use radio waves and magnets to create computerized images. The energy from the radio waves creates patterns formed by different types of tissues. This produces cross-sectional “slices” of the body, including ones that are parallel with the length of the body.

For this test, you lie still on a table as it passes into a tubelike scanner. The scanner has a powerful magnetic field. A computer measures the effect of the magnetic field to create pictures of the inside of your body. You may need more than one set of images. Each one may take two to 15 minutes. This test, which is painless, may last an hour or more. Ask for earplugs if they aren’t offered since there is a loud thumping noise during the scan. If you are claustrophobic, you may be given a sedative before having this test.

Ultrasound

This test uses sound waves to look for abnormalities inside the body. The sound waves bounce off body parts and send back signals, much like sonar on a submarine. The technician puts a gel on the skin of your lower back and then uses a wandlike transducer to press on the skin above your kidneys and send out the sound waves. A computer analyzes the signals and makes an image of the body part being scanned — in this case, your kidney. This test is helpful for determining whether a kidney tumor is a fluid-filled sac, called a cyst, or a solid tumor, which is more likely to be cancer.

Fine needle aspiration biopsy

A biopsy is sometimes done to confirm the diagnosis of kidney cancer and give additional information to determine the appropriate treatment. In most cases of suspected kidney cancer, no biopsy is taken. The imaging tests often give enough information to proceed to surgery to remove the suspected cancer. After surgery, the diagnosis is confirmed by looking at the surgical specimen under the microscope.

If you need a biopsy, your doctor inserts a thin needle through your skin to remove fluid or small pieces of tissue from your kidney. Your doctor then sends the sample to a specialist, called a pathologist, who looks for abnormal cells under a microscope. It usually takes several days for the results of your biopsy to come back.

 
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