As part of your melanoma care plan you may need to have diagnostic tests and scans. This is important for staging, to determine your treatment plan and to monitor for recurrence. As well as a physical examination your specialist may order blood tests and imaging scans or xrays. The frequency and type of tests are dependent on the stage and characteristics of your melanoma.
Types of Scans and their use in melanoma management
An ultrasound is a painless and safe test that uses sound waves to create images of organs and internal structures. Ultrasound examination of the lymphatic drainage area and regional lymph nodes may aid in the early detection of lymph node metastasis in cutaneous melanoma.
An Xray uses electromagnetic radiation to take images of the body. A chest Xray may be done to help determine if melanoma has spread to the lungs.
CT (computerised tomography) scans
A CT scan, commonly known as a CAT scan(computerised axial tomography) , is a specialised Xray test that can make an image of every type of body structure at once including bone, blood vessels and soft tissue. This test can show if any lymph nodes are enlarged or if organs such as the lungs or liver have suspicious spots, which might be from the spread of melanoma.
CT-guided needle biopsy: CT scans can also be used to help guide a biopsy needle into a suspicious area within the body.
MRI (magnetic resonance imaging)
An MRI scan uses magnetic field and radiowaves to produce images of your body. MRI scans are very helpful in looking at the brain and spinal cord.
PET (positron emission tomography)
A PET scan uses a special dye that has radioactive traces. These traces are injected into a vein in your arm. Your organs and tissues then absorb the tracer which will measure important functions such as blood flow and oxygen use. A PET scan can help show if the cancer has spread to lymph nodes or other parts of the body. It is most useful in people with more advanced stages of melanoma and is not usually done in people with early-stage melanoma.
A bone scan uses a small dose of radioactive material injected into a vein and a specialised camera to take pictures of your skeleton. A bone scan may be used to detect melanoma metastases in the bones.
Blood tests are not used to diagnose melanoma, but some tests may be done before or during treatment, especially for more advanced melanomas.
Doctors often test blood for levels of a substance called lactate dehydrogenase (LDH) before treatment. If the melanoma has spread to distant parts of the body, a high LDH level is a sign that the cancer may be harder to treat.