Overview

Unfortunately, there are no blood or urine tests that detect the presence of kidney cancer. When kidney cancer is suspected, your doctor will order a kidney imaging study.  The initial imaging study is usually an ultrasound or CT scan . In some cases, a combination of imaging studies may be needed to completely evaluate the tumor. ¹

If cancer is suspected, you should be evaluated to see if it has spread beyond the kidney (metastasized). An evaluation for metastasis includes an abdominal CT scan or MRI, chest X-ray and blood tests. A bone scan is also recommended if you have bone pain, recent bone fractures, or certain abnormalities on your blood tests. Additional tests may be ordered if your doctor feels it is necessary.

Kidney cancer has the tendency to grow into the renal vein and vena cava . The renal vein is the kidney’s primary draining vein and the vena cava is the vein that takes blood to the heart. The portion of the cancer that extends into these veins is called “tumor thrombus.” Imaging studies, particularly MRI, can help determine if tumor thrombus is present.

Here are the most common tests used to diagnose and evaluate kidney cancer: ²

Computed Tomography (CT scan)

A CT scan is a highly specialized x-ray used to visualize internal organs and provides a very accurate cross section picture of specific areas of the body.  It is one of the primary imaging tools for assessing kidney cancer.

CT scans are more detailed then ordinary x-rays, taking pictures of your organs one thin slice at a time from different angles. Then a computer puts the images together to show the size and location of any abnormalities. To enhance the image of the abdominal organs, dye may be swallowed before the scan. An IV may also be placed for injection of additional contrast dye. There is generally no pain associated with the CT scan, but the IV dye may cause a hot flushing sensation. Some people may also experience an allergic reaction to IV dye (also called IV contrast), especially people who are allergic to iodine. Depending on the part of the body visualized, dietary restrictions may be required before to the procedure.

CT scanning technology has recently been improved by the development of a method called spiral CT scanning.  This type of CT scan is faster and gives a better image than older CT methods.

Magnetic Resonance Imaging (MRI)

An MRI is a highly specialized scan that is similar to a CT scan, but may be better for assessing certain areas of the body like the bones. It creates an accurate cross-section picture of specific organs within the body to allow for a layer-by-layer examination. An MRI is usually not a painful procedure. Because it uses a powerful magnet to produce the images, people with metal in their body — such as prosthetic hip replacements, pacemakers, or metal plates – should discuss the use of an MRI with their physician and the MRI technician before the scan is performed. The test may require the patient to lie still for a long time usually in a narrow space. This may be difficult for people who do not like closed in spaces. MRI scans are often used when CT scans can not effectively view an area of the body.

Bone Scan

A bone scan is used to check for the spread of cancer to the bones. It is done by injecting small amounts of a special radioactive material through a vein into your bloodstream. This material is carried to the bone and collects in areas where there is a lot of bone activity. The test can identify both cancerous and non-cancerous diseases but cannot distinguish between cancer and other conditions such as arthritis when used alone. That is why other tests may be needed, such as x-rays or CT scans.

PET Scan (Positron Emission Tomography)

A PET scan is a very specialized diagnostic study that provides information about how extensively a cancer has spread, based on certain activities of the cells. PET scans are typically used for breast, colorectal, ovarian, lymphoma, lung, melanoma, and head & neck cancer. The effectiveness of PET scans for kidney cancer is still being studied.

Ultrasonography (ultrasound or US)

If there is blood in the urine, an ultrasound of the abdomen with special attention to the kidneys, ureters, and bladder may be ordered. Usually no preparation is needed for this test and it is generally not painful. It uses sound waves to produce images of internal organs. That helps the radiologist to detect any masses that may be present. A wand called a transducer is passed over the skin, and emits sound waves that are detected as echoes bouncing back off internal organs. The echo-pattern images produced by kidney tumors look different from those of normal kidney tissue. This test may be used for initial diagnosis of a kidney mass or to help visualize a mass when a fine needle biopsy is done (see “Biopsy Procedure” below).

Intravenous Pyelogram (IVP)

An intravenous pyelogram (IVP) test may also be used. Special dye is injected into a blood vessel, usually in the arm. The dye circulates through the blood stream to the different organs of the body including the kidneys. X-rays are taken of the kidneys as the dye circulates through them. This will identify any abnormalities within the kidney. If either the ultrasound or IVP is abnormal, a CT scan may be ordered.

Chest X-ray

A plain x-ray of the chest may be done to see if the cancer has spread to the lungs. If something is seen on the x-ray, the doctor may order a CT scan of the chest to help determine what it is.

Angiography

This procedure is used to visualize location and function of arteries. A catheter is usually threaded up a large artery in the leg into an artery leading to your kidney (renal artery). A contrast dye is then injected into the artery to outline blood vessels. Angiography can outline the blood vessels that supply a kidney tumor, which can help a surgeon better plan an operation.

Biopsy Procedure

If, after diagnostic tests are completed, there is a strong suspicion that the kidney mass is malignant (cancerous), surgical removal of the kidney (nephrectomy) will be performed immediately. If the diagnostic test results are not clear, a biopsy may be performed. During a biopsy procedure a small sample of tissue is removed from the mass and examined to determine whether it is benign or malignant. There are several ways to perform a biopsy of a kidney mass. The most common method is a procedure called a fine needle aspiration (FNA) or fine needle biopsy. Using ultrasound or a CT scanner for guidance, the doctor will insert a long thin needle through the skin directly into the mass and remove the sample tissue. This is generally not a painful procedure.  A pathologist will evaluate the biopsy tissue under a microscope to determine if it is benign or malignant. If there is clear evidence that the cancer has spread at the time the kidney mass is discovered, a biopsy may be taken from an area of where it spread, instead of from the kidney. This may be recommended to reduce risk of bleeding, if the metastatic area is more easily accessible than the kidney.

Other Tests

In addition to the tests described above, your doctor may order one or more of the following lab tests to complete your evaluation.

Urinalysis

Urinalysis is usually part of a complete physical exam. Microscopic and chemical tests are performed that will detect small amounts of blood and other substances not seen with the naked eye.  About half of all patients with renal cell cancer will have blood in their urine. Microscopic examination of urine samples (called urine cytology) can also detect cancer cells in the urine.

Blood tests

A complete blood count and chemical test of the blood can detect findings associated with kidney cancer. Anemia (too few red blood cells) is very common. Erythrocytosis (too many red blood cells) may also occur because some of these renal cancers produce a hormone (erythropoietin) that can increase red blood cell production by the bone marrow.

1. “Kidney Cancer”, American Urological Association Foundation, www.urologyhealth.org , URL: http://www.urologyhealth.org/adult/index.cfm?cat=04&topic=124
2. “About Kidney Cancer”, Kidney Cancer Association, www.kidneycancer.org , URL: http://www.kidneycancer.org/knowledge/learn/about-kidney-cancer

While clinical studies support the effectiveness of the da Vinci^® System when used in minimally invasive surgery, individual results may vary. Surgery with the da Vinci Surgical System may not be appropriate for every individual. Always ask your doctor about all treatment options, as well as their risks and benefits.

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