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| Detailed Guide: Kidney Cancer |
How Is Kidney Cancer (Renal Cell Carcinoma) Diagnosed? |
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Signs and Symptoms of Kidney Cancer
Unfortunately, early kidney cancers do not usually cause any signs or
symptoms, but larger ones may. 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 or lump on the side or lower back
- fatigue
- unexplained weight loss
- fever that is not caused by a cold or other infection and
that doesn't go away after a few weeks
- swelling of ankles and legs (edema)
These symptoms may be caused by cancer, but more often they are due to
non-cancerous diseases. For example, blood in the urine may be a sign
of kidney, bladder, or prostate cancer, but most often it is caused by
a bladder infection or a kidney stone. Still, if you have any of these
symptoms, consult a doctor so that the cause can be evaluated and
treated, if needed.
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 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 and/or the results of the physical exam suggest kidney
cancer might be present, more involved tests will likely be done. These
might include imaging tests and/or lab tests.
Imaging Tests
Imaging tests use x-rays, magnetic fields, or radioactive substances to
create pictures of the inside of your body. Imaging tests may be done
for a number of reasons, including to help find out whether a
suspicious area might be cancerous, to learn how far cancer may have
spread, and to help determine if treatment has been effective.
Unlike most other cancers, doctors can often be fairly certain of a
diagnosis of kidney cancer without the need for a biopsy (removal of a
sample of the tumor to be looked at under a microscope). In many cases,
imaging tests can give doctors a reasonable amount of certainty that a
kidney mass is (or is not) cancerous. In some cases, however, a biopsy
may be needed to be sure.
Computed tomography (CT) scans, magnetic resonance imaging (MRI) scans,
intravenous pyelograms, and ultrasound can be very helpful in the
diagnosis of most kinds of kidney tumors, although patients rarely need
all of these tests. Other tests described here, 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 or CAT) Scan
The CT or CAT scan is an x-ray test that produces detailed
cross-sectional images of your body. Instead of taking one picture,
like a regular x-ray, a CT scanner takes many pictures as it rotates
around you while you lie on a table. A computer then combines these
pictures into images of slices of the part of your body being studied.
Unlike a regular x-ray, a CT scan creates detailed images of the soft
tissues in the body.
After the first set of pictures is taken you may be asked to drink a
contrast solution and/or receive an IV (intravenous) line through which
a contrast dye is injected. This helps better outline structures in
your body. A second set of pictures is then taken.
The contrast 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 the doctor if you have ever had a reaction to
any contrast material used for x-rays.
CT scans take longer than regular x-rays. You need to lie still on a
table while they are being done. During the test, the table moves in
and out of the scanner, a ring-shaped machine that completely surrounds
the table. You might feel a bit confined by the ring you have to lie in
while the pictures are being taken.
In recent years, spiral
CT (also known as helical CT) has become available in many
medical centers. This type of CT scan uses a faster machine. The
scanner part of the machine rotates around the body continuously,
allowing doctors to collect the images much more quickly than standard
CT. This lowers the chance of "blurred" images occurring as a result of
breathing motion. It also lowers the dose of radiation received during
the test. The biggest advantage may be that the "slices" it images are
thinner, which yields more detailed pictures and allows doctors to look
at suspicious areas from different angles.
CT scanning is one of the most useful tests for finding and looking at
a mass inside your kidney. It is also useful in checking whether or not
a cancer has spread to organs and tissues beyond the kidney. The CT
scan will provide precise information about the size, shape, and
position of a tumor, and can help find enlarged lymph nodes that might
contain cancer.
Magnetic Resonance Imaging (MRI)
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.
MRI scans are a little more uncomfortable than CT scans. First, they
take longer -- often up to an hour. Second, you have to lie inside a
narrow tube, which is confining and can upset people with
claustrophobia (a fear of enclosed spaces). Newer, "open" MRI machines
can sometimes help with this if needed. The machine also makes buzzing
and clicking noises that you may find disturbing. Some centers provide
headphones with music to block this 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 is allergic to the CT contrast. MRI scans may also be
done if there's a chance that the cancer involves a major vein in the
abdomen (the inferior vena cava). 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 (ultrasonography or US)
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. It emits 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 be helpful in determining if a kidney mass is solid or
filled with fluid. The echo patterns produced by most kidney tumors
look different from those of normal kidney tissue. Different echo
patterns also can distinguish some types of benign and malignant kidney
tumors from one another. If a kidney biopsy is needed, this test can be
used to guide a biopsy needle into the mass to obtain a sample.
Positron Emission Tomography (PET) Scan
PET scans involve injecting a form of radioactive sugar (known as
fluorodeoxyglucose or FDG) into the blood. The amount of radioactivity
used is very low. Because cancer cells in the body are growing rapidly,
they absorb large amounts of the radioactive sugar. A special camera
can then create a picture of areas of radioactivity in the body. The
picture is not finely detailed like a CT or MRI scan, but it provides
helpful information about your whole body.
This test can be useful to see if the cancer may have spread to lymph
nodes near the kidney. PET scans can also be useful if your doctor
thinks the cancer may have spread but doesn't know where. PET scans can
be used instead of several different x-rays because they scan your
whole body.
Some newer machines are able to perform both a PET and CT scan at the
same time (PET/CT scan). This allows the radiologist to compare areas
of higher radioactivity on the PET with the appearance of that area on
the CT.
Intravenous Pyelogram (IVP)
An intravenous pyelogram is an x-ray of the urinary system taken after
a special dye is injected into a vein. This dye travels from the
bloodstream into the kidneys and then passes into the ureters and
bladder. An IVP can be useful in finding abnormalities of the urinary
tract, such as cancer, but you might not need an IVP if you have
already had a CT or MRI.
Angiography
Like the IVP, this x-ray test also uses a contrast dye. A catheter is
usually threaded up a large artery in your leg into the artery leading
to your kidney (renal artery). The dye is then injected into the artery
to outline blood vessels. Because angiography can outline the blood
vessels that supply a kidney tumor, it can help a surgeon plan an
operation. Angiography can also help diagnose renal cancers since the
blood vessels usually have a special appearance with this test.
Chest X-ray
If kidney cancer has been diagnosed (or is suspected), a plain x-ray of
your chest may be done to see if the cancer has spread to your lungs.
This is very unlikely unless the cancer is far advanced. This x-ray can
be done in any outpatient setting. If the results are normal, you
probably don't have cancer in your lungs.
Bone Scan
A bone scan can help show if a cancer has metastasized (spread) to your
bones. For this test, a small amount of low-level radioactive material
is injected into a vein (intravenously, or IV). The substance settles
in areas of damaged bone throughout the entire skeleton over the course
of a couple of hours. You then lie on a table for about 30 minutes
while a special camera detects the radioactivity and creates a picture
of your skeleton.
Areas of active bone changes appear as "hot spots" on your skeleton --
that is, they attract the radioactivity. These areas may suggest the
presence of metastatic cancer, but arthritis or other bone diseases can
also cause the same pattern. To distinguish between these conditions,
your cancer care team may use other imaging tests such as simple x-rays
or MRI scans to get a better look at the areas that light up, or they
may even take biopsy samples of the bone.
Bone scans are done mainly when there is reason to think the cancer may
have spread to the bones (because a person is having symptoms like bone
pain). PET scans can usually show the spread of cancer to bones as
well, so if you've had a PET scan you might not need a bone scan.
Lab Tests
Lab tests are not usually used to diagnose kidney cancer, but they can
sometimes give the first hint that there may be a problem with the
kidneys. They are also done to get a sense of a person's overall health
and to help tell if cancer may have spread to other areas. Prior to
surgery, they can help tell if a person is healthy enough to have an
operation.
Urinalysis
Urinalysis (urine testing) is sometimes part of a complete physical
exam, but it may not be done as a part of more routine physicals. It is
likely to be one of the first tests done if kidney cancer is a
possibility.
Microscopic and chemical tests are done on the urine to look for 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. Sometimes special microscopic examination of urine samples
(called urine cytology) will show actual cancer cells in the urine.
Complete Blood Count
A complete blood count can detect findings sometimes seen with renal
cell cancer. Anemia (having too few red blood cells) is very common.
Less often, a person may have too many red blood cells because the
kidney cancer makes 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 may have kidney
cancer, as it can affect the levels of certain chemicals in the blood.
For example, high levels of liver enzymes are sometimes found, although
the reasons for this are not known. High blood calcium levels may
indicate that cancer is spread to the bones, and may therefore prompt a
doctor to order a bone scan.
Fine Needle Aspiration (FNA) Biopsy
This test is rarely used to diagnose kidney tumors. Imaging studies
usually provide enough information for a surgeon to decide whether or
not an operation is needed.
A fine needle aspiration (FNA) biopsy is sometimes used to get a small
sample of cells from a suspicious area if imaging test results are not
conclusive enough to warrant removing a kidney. It may also be done to
confirm the diagnosis of cancer if a person's health is too poor for
surgery and other local treatments (such as arterial embolization or
cryotherapy) are being considered.
For this test, the skin where the needle is to be inserted is first
numbed with local anesthesia. The doctor directs a hollow needle into
the area while looking at your kidney with either ultrasound or CT
scans. Unlike ultrasound, CT doesn't provide a continuous picture, so
the needle is inserted in the direction of the mass, a CT image is
taken, and the direction of the needle is guided based on the image.
This is repeated a few times until the needle is within the mass. A
small sample of the target area is sucked (aspirated) into a syringe
and looked at under the microscope to see if cancer cells are present.
In cases where the doctors think kidney cancer may have spread to other
sites, they may perform a biopsy of the metastatic site instead of the
kidney.
Fuhrman Grade
The Fuhrman grade is determined by looking at kidney cancer cells
(taken during a biopsy or during surgery) under a microscope. It is
used by many doctors as a way to describe how aggressive the cancer is
likely to be. The grade is based on how closely the cancer cells'
nuclei (part of a cell in which DNA is stored) look like those of
normal kidney cells.
Renal cell cancers are usually graded on a scale of 1 through 4. Grade
1 renal cell cancers have cell nuclei that differ very little from
normal kidney cell nuclei. These cancers usually grow and spread slowly
and tend to have a good outlook (prognosis). At the other extreme,
grade 4 renal cell cancer nuclei look quite different from normal
kidney cell nuclei and have a worse prognosis.
Although the cell type and grade are sometimes helpful in predicting a
prognosis, the cancer's stage
is by far the best predictor of survival. The stage describes the
cancer's size and how far it has spread beyond the kidney. Staging is
explained in the section, "How Is Kidney Cancer (Renal Cell Carcinoma)
Staged?" Last Revised: 10/22/2007
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