Imaging Tests for Melanoma

When you need tests for skin cancer—and when you don’t

Imaging tests are tests such as CT scans and PET-CT scans. They take pictures, and sometimes they give doctors important information.

If you have advanced-stage skin cancer, imaging tests may help. They can help your doctor see if the cancer has spread or come back after treatment.

But the tests usually don’t help if you have early-stage skin cancer. Here’s why.

What is melanoma?

Melanoma is the most serious type of skin cancer. It usually appears as a dark, uneven spot on the skin. It’s usually removed during an outpatient surgical procedure.

What do early-stage or advanced-stage mean?

Early-stage means that the cancer hasn’t grown much. Cancers in a very early stage usually haven’t spread to other parts of the body. If the cancer has not spread, treatment is more likely to be successful.

Advanced-stage usually means that the cancer is bigger and has probably spread.

It’s important to know the stage of a cancer. It helps you and the doctor decide on your treatment.

How does the doctor find the stage of skin cancer?

If you have been diagnosed with melanoma, your doctor will:

  • Take your medical history.
  • Do a thorough physical exam.
  • Examine the size, depth, and appearance of the skin cancer.
  • Check nearby lymph nodes (part of your body’s immune system). Your doctor may do a biopsy of the lymph nodes. To do this, a little tissue is removed and examined.

Based on these exams, your doctor usually has enough information to know if the cancer is in an early or an advanced stage.

Tests usually don’t help at an early stage.

If your doctor says your cancer is most likely in the earliest stages, imaging tests usually don’t give any extra information. In fact, imaging tests for early-stage skin cancer may create other problems.

There are problems with imaging tests at an early stage.

Some doctors will order imaging tests, such as a chest X-ray, brain MRI, CT scan, or PET-CT scan. They think the tests will help show if the cancer has spread or help the surgeon find all the cancer. But these tests do not find skin cancers very well. So they don’t give doctors helpful information about the size of the cancer.

In addition, it is very unlikely that an early-stage melanoma has spread. Because of this, the test results won’t give new information or change the treatment you would have had anyway.

The tests may find false alarms that can lead to more tests. Many of these tests use radiation, which can lead to new cancers. The tests can also be expensive.

When you might need an imaging test.

You doctor should not order any imaging tests unless there’s a good reason to think the skin cancer has spread.

If there are signs that the cancer has spread to your lymph nodes or beyond, then you may need an imaging test.

This report is for you to use when talking with your healthcare provider. It is not a substitute for medical advice and treatment. Use of this report is at your own risk.

© 2017 Consumer Reports. Developed in cooperation with the Society of Surgical Oncology.