Melanoma: Tests After Diagnosis
Once you’re diagnosed with melanoma, you will need more tests. These tests help your
healthcare providers learn more about your cancer. They can help show if the cancer
has grown into nearby areas or spread to other parts of the body. The test results
help your providers decide how to treat the cancer. If you have any questions about
these or other tests, talk with your healthcare team. You may need 1 or more of these
tests:
Sentinel lymph node biopsy
You may need a sentinel lymph node biopsy if you have a thick melanoma or one with
other features that make it more likely to have spread. This procedure removes nearby
lymph nodes to check for cancer cells. It’s done because melanoma often spreads first
to the lymph nodes.
In a group of lymph nodes, cancer is most likely to go to 1 or 2 lymph nodes first.
These lymph nodes are called sentinel lymph nodes. During the procedure, a surgeon
removes 1 or more sentinel lymph nodes. Any nodes removed are then looked at for cancer
cells. If no cancer is found, the melanoma is unlikely to have spread beyond this
point. The other lymph nodes in the group can be left in place. Results of a sentinel
lymph node biopsy help your provider figure out what treatment you may need.
During a sentinel node biopsy:
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The process starts with lymph node mapping. This is a way to find out which lymph
node nearest to the melanoma is the sentinel node. To fine the sentinel lymph node
(or nodes), the provider may use a radioactive tracer, a blue dye, or both. The provider
injects a small amount of radioactive tracer into your skin near the melanoma site.
It takes about an hour for the tracer to follow the same path as a melanoma cell would
to the nearest lymph node.
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The provider uses a special device that detects radioactivity a lot like a Geiger
counter does. This helps to show where the cancer cells are most likely to go. The
provider also may inject a blue dye that travels to the lymph nodes. The lymph node
that shows up with radioactivity or with the blue dye is called the sentinel lymph
node.
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The provider makes a small incision to remove this lymph node (or nodes).
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Right after removing the lymph node, your provider may do a wide local excision. This
is a surgery to remove more tissue around the melanoma. This can help prevent melanoma
from coming back (recurring).
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The sentinel lymph node is examined in a lab for cancer cells.
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If it doesn't have melanoma cells, you may not need more tests. The provider will
leave the other lymph nodes in place.
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If the removed sentinel lymph node (or nodes) has melanoma cells, your provider may
decide to remove all the lymph nodes in that region if there are non-sentinel lymph
nodes that may have cancer present. This is called lymph node dissection. You might
also need imaging tests such as CT scans, MRI, or a PET scan. You may also need blood
tests.
FNA biopsy
If your healthcare provider thinks the cancer has spread to a certain lymph node or
organ, you may have an FNA biopsy. This is to confirm if cancer is present. You may
first get a local numbing medicine. The test rarely causes much discomfort and leaves
little scarring. The provider uses a syringe with a small needle to remove a small
sample of tissue from the node or organ. The provider may use imaging tools, such
as a CT scan or ultrasound, during the biopsy. This is to help guide the needle to
the right place. The tissue sample is examined in a lab for cancer cells.
CT scan
This test helps your provider see where the melanoma is located and if it has spread
to other parts of your body. It's helpful for finding melanoma in the chest, abdomen,
and pelvis.
A CT scan uses a series of X-rays and a computer to create detailed images of the
inside of the body. During the test, you lie still on a table as it slowly slides
through the center of the CT scanner. The scanner directs a beam of X-rays at your
body. A CT scan is painless. You may be asked to hold your breath one or more times
during the scan. You may need to drink a dye (contrast medium) or get it in an IV
(intravenous) injection before the test.
The IV dye allows your provider to better see lymph nodes and other tissues. Some
people have a temporary warm feeling (flushing) just after the injection. The ingested
dye will gradually pass through your system and exit through your bowel movements.
Tell your provider if you have ever had a reaction to contrast material in the past,
such as hives or trouble breathing. Tell your provider if you have these reactions
during the test.
MRI
This test is helpful in looking at your brain and spinal cord. MRI may also be used
if the results of an X-ray or CT scan aren’t clear. MRIs use radio waves, magnets,
and a computer to make detailed images of the inside of the body.
For this test, you lie still on a table as it passes through a tubelike scanner. If
you're not comfortable in small spaces, you may be given medicine before the test
to help you relax. The scanner directs a beam of radio waves at the area of the body
being examined. You may need more than 1 set of images. Each may take 2 to 15 minutes.
This test is painless. It may last an hour or more. The machine is loud during the
test. You can ask for earplugs or headphones with music. A type of contrast dye might
be given before the MRI.
PET scan
A PET scan can examine your entire body. For this test, you either swallow or are
injected with a mildly radioactive substance (tracer), usually a form of sugar. The
PET scan will show where in your body the sugar is being used the most. This helps
find active cells that are dividing quickly, such as cancer cells.
You’ll lie still on a table that is pushed into the PET scanner. It will rotate around
you and take pictures. Other than the injection, a PET scan is painless and noninvasive.
Some people are sensitive to the substance and may have nausea, a headache, or vomiting.
You may have a PET/CT scan. This machine can do both a PET and CT scan at the same
time, so areas that show up on the PET scan can be compared with the more detailed
image of the CT scan.
Blood tests
Your provider may tell you to get a lactate dehydrogenase (LDH) test before you have
treatment. LDH is an enzyme in the blood. Sometimes LDH blood levels are high when
many cancer cells are present or when the liver has been damaged by cancer. This test
can be helpful in showing if cancer has spread.
Your provider may want you to have other blood tests to check blood cell counts and
blood chemistry before or during treatment. It can show how well the bone marrow,
liver, and kidneys are doing.
Chest X-ray
A chest X-ray is done to see if there are any changes in your lungs. This may show
that the melanoma has spread. An X-ray uses a small amount of radiation to make an
image of organs and bones inside the body. The test can also spot enlarged lymph nodes
in your chest area. This test takes a few minutes and causes no pain.
Working with your healthcare provider
Your provider will talk with you about which tests you’ll have. Make sure to prepare
for the tests as instructed. Ask questions and talk about any concerns you have.