- These cancers can sometimes grow quite large without causing any pain or other problems.
- Because the kidneys are deep inside the body, small kidney tumors cannot be seen or felt during a physical exam.
- There are no recommended screening tests for kidney cancer in people who are not at increased risk. This is because no test has been shown to lower the overall risk of dying from kidney cancer.
Some tests can find some kidney cancers early, but non of these are recommended to screen for kidney cancer in people at average risk.
A routine urine test (urinalysis), which is sometimes part of a complete medical checkup, may find small amounts of blood in the urine of some people with early kidney cancer. But many things other than kidney cancer cause blood in the urine, including urinary tract infections, bladder infections, bladder cancer, and benign (non-cancerous) kidney conditions such as kidney stones. And some people with kidney cancer do not have blood in their urine until the cancer is quite larger and might have spread to other parts of the body.
Imaging tests such as computed tomography (CT) scans and magnetic resonance imaging (MRI) scans can often find small kidney cancers, but these tests are expensive. Ultrasound is less expensive and can also detect some early kidney cancers. One problem with these tests is that they can’t always tell benign tumors from small renal cell carcinomas.
Often, kidney cancers are found incidentally (by accident) during imaging tests for some other illness such as gallbladder disease. These cancers usually are causing no pain or other symptoms when they are found. The survival rate for these kidney cancers is very high because they are usually found at a very early stage.
For People at Increased Risk of Kidney Cancer
People who have certain inherited conditions, such as von Hippel-Lindau disease, have a higher risk of kidney cancer. Doctors often recommend that these people get regular imaging tests such as CT, MRI, or ultrasound scans to look for kidney tumors. Kidney cancers that are found early with these tests can often be cured.
It is important to tell your doctor if any of your family members (blood relatives) has or had kidney cancer, especially at a younger age, or if they have been diagnosed with an inherited condition linked to this cancer, such as von Hippel-Lindau disease. Your doctor may recommend you consider genetic counseling and testing to see if you have the condition.
Before having genetic tests, it’s important to talk with a genetic counselor so that you understand what the tests can — and can’t — tell you, and what any results would mean. Genetic tests look for the gene mutations that cause these conditions in your DNA. They are used to diagnose these inherited conditions, not kidney cancer itself. Your risk may be increased if you have one of these conditions, but it does not mean that you have (or definitely will get) kidney cancer.
Signs and Symptoms of Kidney Cancer
Early kidney cancers do not usually cause any signs or symptoms, but larger ones might. Some possible signs and symptoms of kidney cancer include:
- Blood in the urine (hematuria)
- Low back pain on one side (not caused by injury)
- A mass (lump) on the side or lower back
- Fatigue (tiredness)
- Loss of appetite
- Weight loss not caused by dieting
- Fever that is not caused by an infection and that doesn’t go away
- Anemia (low red blood cell counts)
These signs and symptoms can be caused by kidney cancer (or another type of cancer), but more often they are caused by other, benign, diseases. For example, blood in the urine is most often caused by a bladder or urinary tract infection or a kidney stone. Still, if you have any of these symptoms, see a doctor so that the cause can be found and treated, if needed.
How is Kidney Cancer Diagnosed?
Kidney cancer might be found because of signs and symptoms a person is having, or it might be found because of lab testing or imaging tests a person is getting for another reason. If cancer is suspected, tests will be needed to confirm the diagnosis.
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 a complete medical history to check for risk factors and to learn more about your symptoms.
A physical exam can provide information about signs of kidney cancer and other health problems. For example, the doctor may be able to feel an abnormal mass when he or she examines your abdomen.
If symptoms or the results of the physical exam suggest you might have kidney cancer, more tests will probably be done. These might include lab tests and imaging tests.
Lab tests cannot 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, they 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 an operation.
Urinalysis (urine testing) is sometimes part of complete physical exam, but it may not be done as a part of more routine physicals. This test may be done if your doctor suspects a kidney problem.
Microscopic and chemical tests are done on a urine sample to look for small amounts of blood and other substances not seen with the naked eye. About half of all patients with renal cancer will have blood in their urine. If the patient has transitional cell carcinoma (in the renal pelvis, the ureter, or the bladder), sometimes a special microscopic exam of the urine sample (called urine cytology) will show actual cancer cells in the urine.
Complete Blood Count
The complete blood count (CBC) is a test that measures the amounts of different cells in the blood, such as red blood cells, white blood cells, and platelets. This test result is often abnormal in people with renal cell cancer. Anemia (having too few red blood cells) is very common. Less often, a person may have too may red blood cells (called polycythemia) because the kidney cancer cells make a hormone (erythropoietin) that causes the bone marrow to make more red blood cells.
Blood counts are also important to make sure a person is healthy enough for surgery.
Blood Chemistry Tests
Blood chemistry tests are usually 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 liver enzymes are sometimes found. High blood calcium levels may indicate that cancer has spread to the bones, and may therefore prompt a doctor to order a bone scan. Blood chemistry tests also look at kidney function, which is especially important if certain imaging tests or if surgery is planned.
Imaging tests use x-rays, magnetic fields, sound waves, or radioactive substances to create pictures of the inside of your body. Imaging tests can be done for a number of reasons:
- To help find out whether a suspicious area might be cancer
- To learn how far cancer has spread
- To help determine if treatment has been effective
- To look for signs of the cancer coming back
Unlike most other cancers, doctors can often diagnose kidney cancer fairly certainly based on imaging tests without doing a biopsy (removing a sample of the tumor to be looked at under a microscope). In some patients, however, a biopsy may be needed to be sure.
Computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, and ultrasound can be very helpful in diagnosing most kinds of kidney tumors, although patients rarely need all of these tests. Other tests, such as chest x-rays and bone scans, are more often used to help determine if the cancer has spread (metastasized) to other parts of the body.
Computed Tomography (CT) Scan
The CT scan uses x-rays to produce detailed cross-sectional images of your body. It is one of the most useful tests for finding and looking at a tumor in your kidney. It can provide precise information about the size, shape, and position of a tumor. It is also useful for checking to see if a cancer has spread to nearby lymph nodes or to organs and tissues outside of the kidney. If a kidney biopsy is needed, this test can also be used to guide a biopsy needle into the mass to obtain a sample.
Instead of taking one picture, like a regular x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into images of slices of the part of your body being studied.
A CT scanner has been described as a large donut, with a narrow table that slides in and out of the middle opening. You will need to lie still on the table while the scan is being done. CT scans take longer than regular x-rays, and you might feel a bit confined by the ring while the pictures are being taken.
Before the test, you might be asked to drink 1 to 2 pints of a liquid called oral contrast. This helps outline the intestine so that certain areas are not mistaken for tumors. You might also receive an IV (intravenous) line through which a different kind of contrast dye (IV contrast) is injected. This helps better outline structures in your body. The injection may cause some flushing (a feeling of warmth, especially in the face). Some people are allergic and get hives. Rarely, more serious reactions like trouble breathing or low blood pressure can occur. Be sure to tell your doctor if you have any allergies or if you have ever had a reaction to any contrast material used for x-rays.
CT contrast can damage the kidneys. This happens more often in patients whose kidneys are not working well in the first place. Because of this, your kidney function will be checked with a blood test before you get IV contrast.
Magnetic Resonance Imaging (MRI) scan
Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into a very detailed image of parts of the body.
A contrast material called gadolinium is often injected into a vein before the scan to better see details. This contrast material isn’t used in people on dialysis, because in those people it can rarely cause a severe side effect called nephrogenic systemic fibrosis.
MRI scans take longer than CT scans — often up to an hour — and are a little more uncomfortable. You have to lie inside a narrow tube, which is confining and can upset people with claustrophobia (a fear of enclosed spaces). Special, open MRI machines can sometimes help with this if needed, but the drawback is that the pictures may not be as clear. MRI machines also make buzzing and clicking noises that many people find disturbing. Some centers provide headphones with music to block this noise out.
MRI scans are used less often than CT scans in people with kidney cancer. They may be done in cases where CT scans aren’t practical, such as if a person can’t have the CT contrast dye because they have an allergy to it or they don’t have good kidney function. MRI scans may also be done if there’s a chance that the cancer has grown into major blood vessels in the abdomen (like the inferior vena cava), because they provide a better picture of blood vessels than CT scans. Finally, they may be used to look for possible spread of cancer to the brain or spinal cord if a person has symptoms that suggest this might be the case.
Ultrasound uses sound waves to create images of internal organs. For this test, a small, microphone-like instrument called a transducer is placed on the skin near the kidney after a gel is applied. The transducer gives off sound waves and picks up the echoes as they bounce off the tissues in the kidney. The echoes are converted by a computer into a black and white image that is displayed on a computer screen. This test is painless and does not expose you to radiation.
Ultrasound can help find a kidney mass and show if it solid or filled with fluid (kidney tumors are more likely to be solid). Different echo patterns also can help doctors tell some types of benign and malignant kidney tumors from one another.
If a kidney biopsy is needed, this test can also be used to guide a biopsy needle into the mass to obtain a sample.