Tests for Kidney Cancer

Kidney cancer (also known as renal cell cancer, or RCC) might be found because of signs or symptoms a person is having, or it might be found because of lab tests or imaging tests a person is getting for some other reason.

The actual diagnosis of kidney cancer is made by looking at a sample of kidney cells in the lab or sometimes by how the kidney looks on an imaging test.

If you think you have possible signs or symptoms of kidney cancer, it’s important to see a doctor.

Medical history and physical exam

If you have any signs or symptoms that suggest you might have kidney cancer, your doctor will want to take your complete medical history to check for possible risk factors and to learn more about your symptoms.

A physical exam can provide information about possible signs of kidney cancer and other health problems you might have. For example, the doctor may be able to feel an abnormal mass (lump) when they examine your abdomen (belly).

If symptoms or the results of the physical exam suggest you might have kidney cancer, you will probably need to have certain tests. These might include lab tests, imaging tests, or biopsies of the kidney.

If kidney cancer is found, more tests might then be needed to help determine the stage (extent) of the cancer.

Blood tests

Lab tests can’t show for sure if a person has kidney cancer, but they can sometimes give the first hint that there may be a kidney problem.

If cancer has already been diagnosed, blood tests are also done to get a sense of a person’s overall health and to help tell if the cancer might have spread to other areas. They also can help show if a person is healthy enough to have surgery.

Complete blood count (CBC): This test measures the levels of different cells in the blood, which are often abnormal in people with kidney cancer. Anemia (having too few red blood cells) is very common. Less often, a person may have too many red blood cells (called polycythemia). People with kidney cancer sometimes have high levels of blood platelets or of neutrophils, which are a type of white blood cell. Blood counts are also important to make sure a person is healthy enough for surgery.

Blood chemistry tests: These tests are often done in people who might have kidney cancer, because the cancer can affect the levels of certain chemicals in the blood. For example, high levels of calcium, lactate dehydrogenase (LDH), or liver enzymes are sometimes found. Levels of other chemicals, such as alkaline phosphatase, are also routinely tested. Blood chemistry tests also measure kidney function, which is especially important if certain imaging tests or if surgery is planned.

Urine tests

Your urine may be tested if your doctor suspects a kidney problem.

Urinalysis: This test looks at the levels of different chemicals and proteins in a urine sample. The samples can also be checked for red or white blood cells and other substances that can’t be seen with the naked eye. Many people with kidney cancer will have blood in their urine, sometimes in very small amounts. Other parts of this test can help show how well the kidneys and some other organs are working.

Urine cytology: If an imaging test (see below) shows that a person has a tumor in the renal pelvis (the middle part of the kidney, which is attached to the ureter), a test called urine cytology might be done. This test looks for cancer cells in the urine.

Imaging tests to look for kidney cancer

Imaging tests use x-rays, magnetic fields, sound waves, or radioactive substances to create pictures of the inside of your body. Imaging tests might be done for a number of reasons, such as:

• To look for tumors in people who have symptoms or abnormal test results that might be from kidney cancer
• To help guide a needle biopsy (see below)
• To learn how far a kidney cancer has spread
• To help determine if treatment is working
• To look for possible signs of cancer coming back (recurring) after treatment

Unlike most other types of cancer, doctors can sometimes diagnose kidney cancer with a fair amount of certainty using only imaging tests, without needing a biopsy (removing a sample of the tumor). But this isn’t always the case, and often people need a biopsy to make sure their diagnosis is correct.

Computed tomography (CT) scan

A CT scan uses x-rays to make detailed cross-sectional images of your body. A CT scan of the abdomen (belly) can provide precise information about the size, shape, and location of a kidney tumor. CT scans can also show if a cancer has spread to nearby lymph nodes or to other parts of the body, such as the lungs.

A special type of CT scan, known as CT angiography, might sometimes be done to get a better look at the blood vessels around the kidney.

CT-guided needle biopsy: If a kidney biopsy is needed, this test can also be used to guide a biopsy needle into the mass (lump) to get a sample to check for cancer.

When a CT is done to look at the kidneys, an IV (intravenous) contrast dye is often needed to make certain areas stand out better on the scan. This could cause problems in people whose kidneys aren’t working well in the first place, so another type of imaging test, such as an ultrasound or MRI, might be done instead. Your kidney function will be checked with a blood test before you get a CT scan with IV contrast.

Magnetic resonance imaging (MRI)

MRIs use radio waves and strong magnets to create detailed images of the body. MRIs aren’t usually the first imaging test done to look for kidney cancer, but they may be done:

• If a person can’t get the contrast dye for a CT scan because they have an allergy to it or they don’t have good kidney function.
• If there’s a chance that the cancer has grown into major blood vessels in the abdomen, like the inferior vena cava. (MRIs provide a better picture of blood vessels than CT scans.)
• To look at abnormal areas in the brain and spinal cord that might be due to cancer spread.

A special type of MRI, known as MR angiography, might sometimes be done to get a better look at the blood vessels around the kidney.

Ultrasound

Ultrasound uses sound waves and their echoes to create pictures of organs in the body. It can help find a kidney mass and show if it is solid or filled with fluid. (Solid masses are more likely to be tumors.) Different ultrasound patterns can also help doctors tell the difference between some types of benign and malignant (cancerous) kidney tumors.

Ultrasound-guided needle biopsy: If a kidney biopsy is needed, ultrasound can also be used to guide a biopsy needle into the mass to take a sample.

Chest x-ray

An x-ray of the chest may be done if kidney cancer has been diagnosed to see if cancer has spread to the lungs. More often, though, a CT scan of the chest is done instead because it can show more detail. 

Bone scan

A bone scan can help show if cancer has spread to your bones. For this test, you will get an injection of a small amount of low-level radioactive material. It will collect mainly in abnormal areas of bone. A special camera is then used to find the levels of radioactivity in different parts of your body.

This test is only likely to be done if there is reason to think the cancer might have spread to the bones, such as if a person is having bone pain or if blood tests show an increased calcium or alkaline phosphatase level.

Kidney biopsy

For most other types of cancer, a biopsy is needed to confirm the diagnosis. During a biopsy, small pieces of a suspicious area are removed and checked in the lab for cancer cells.

But if kidney cancer is suspected, imaging tests can often provide enough information for a surgeon to decide if surgery is needed. The diagnosis is then confirmed when part or all of the kidney is removed and is looked at in the lab.

There are some situations in which a kidney biopsy might be needed:

• When the results of imaging tests aren’t clear enough to know if surgery is needed.
• To confirm a tumor is cancer if a person might not be treated with surgery, such as with small tumors that will be watched and not treated, or when other treatments are being considered.

When a biopsy is needed, it’s typically done by inserting a thin, hollow needle into the tumor and removing a sample of cells (known as a needle biopsy). Often a CT scan or ultrasound is used to help guide the needle into the tumor.

If the doctor thinks the kidney cancer might have spread to other parts of the body, they may biopsy one of these areas instead of the kidney.

Lab tests on biopsy and surgery samples

Samples from any biopsies (or from surgery to remove all or part of the kidney) are sent to a lab, where they are looked at by a pathologist, a doctor specially trained in diagnosing diseases with lab tests.

If kidney cancer cells are found, further tests might be done to determine which type of kidney cancer it is.

Another important feature is the grade of the cancer, specifically called the Fuhrman grade. This is based on how much the cancer cells look like those of normal kidney cells. Renal cell cancers are usually graded on a scale of 1 to 4.

• Grade 1 cancers have cells that look a lot like normal kidney cells. These cancers usually grow and spread slowly and tend to have a good prognosis (outlook). 
• Grade 4 renal cell cancers look very different from normal kidney cells. These cancers tend to have a worse prognosis.

The kidney cancer's grade is one of the factors in deciding on a treatment.