Diagnosing melanoma

Sunday 1 January, 2017

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On this page: Physical examination | Removing the mole (excision biopsy) | Checking the lymph nodes | Staging the melanoma | Prognosis | Which health professionals will I see? | Key points


Physical examination

If you notice any changes to your skin, your doctor will examine you, paying particular attention to any spots you have identified as changed or suspicious. The doctor will ask if you or your family have a history of melanoma. The doctor may assess the spot using the ‘ABCDE’ criteria:

  • Asymmetry – are the halves of each mole different?
  • Border – are the edges irregular, scalloped or notched?
  • Colour – are there differing shades and colour patches?
  • Diameter – is the spot greater than 6 mm across?
  • Evolving – has the spot changed over time (size, shape, surface, colour, bleeding, itching)?

Some melanomas don’t follow the ‘ABCDE’ criteria, so your doctor may also assess whether the spot is elevated, firm or growing. Your doctor may use a handheld magnifying instrument called a dermascope to see the spot more clearly.

Removing the mole (excision biopsy)

If the doctor suspects that a spot on your skin may be melanoma, the usual procedure is to remove the whole spot (excision biopsy) for examination by a tissue specialist (pathologist). This is generally a simple procedure in your doctor’s office. Your GP may do it, or you may be referred to a dermatologist or surgeon.

You will have an injection of local anaesthetic to numb the area. The doctor will use a scalpel to remove the spot and a narrow margin (2 mm) of healthy tissue around it. The wound will usually be closed with stitches. It is recommended that the entire mole is removed rather than a small sample. This helps ensure an accurate diagnosis and accurate staging of any melanoma found.

A pathologist will examine the tissue under a microscope to determine if it contains melanoma cells. Results are usually ready in about a week, and a follow-up appointment may be arranged to check the wound and remove your stitches. If the mole contains cancerous cells you may need further surgery, such as a wide local excision.

Checking the lymph nodes

Lymph nodes are part of your body’s lymphatic system, which removes excess fluid from tissues, absorbs fatty acids, transports fat, and produces immune cells. There are large groups of lymph nodes in the neck, armpits and groin. Sometimes melanoma can travel through the lymph vessels to other parts of the body.

Your doctor may feel the lymph nodes near the melanoma to see if they are enlarged. This may indicate the cancer has spread to the lymph nodes. To test whether the melanoma has spread, your doctor may recommend that you have a fine needle aspiration biopsy or a sentinel lymph node biopsy.

Fine needle aspiration biopsy

The doctor takes a sample of cells by inserting a thin needle into a suspicious lymph node. Ultrasound is often used to guide the needle to the correct node. The sample is then examined under a microscope to see if it contains cancer cells.

Sentinel lymph node biopsy

You will have an injection of a small amount of radioactive substance into the area where the melanoma was removed. The lymph node that absorbs the injected fluid first is the sentinel lymph node.

If the cancer has spread, the sentinel node is the most likely node to have cancer within it. The surgeon will remove this node to check for cancer cells and determine whether it’s necessary to remove more lymph nodes. The removal of the sentinel lymph node is usually done under a general anaesthetic at the same time as the wide local excision. Your doctor will talk to you about this type of biopsy, and the associated risks and benefits.

If cancer cells are found in the sentinel lymph node, the remaining nodes in the area may also be removed. This is to treat the cancer locally to try to stop the melanoma coming back in the same area or spreading from the primary site.

The risk of having melanoma in the lymph nodes increases with the thickness of the melanoma and is very low for thin melanomas. For this reason, sentinel node biopsy will usually only be offered to people if the Breslow thickness (see below) of their melanoma is over 1 mm.

A sentinel lymph node biopsy can provide information that helps predict the risk of melanoma spreading to other parts of the body. This can help your doctor plan your treatment. It may also allow you to access new clinical trials.

Pathology report

If you have melanoma, the pathologist’s report will provide your treatment team with information to help plan treatment and determine your prognosis. The following factors may be included:

Breslow thickness

This is a measure of the thickness of the tumour in millimetres from the epidermis to its deepest point in the skin. The thicker a melanoma, the more likely it will recur or spread to other parts of the body. Melanomas are classified as:

  • in situ – found only in the outer layer of the skin
  • thin – less than 1 mm
  • intermediate – 1–4 mm
  • thick – greater than 4 mm.
Clark level

This describes how many layers of skin the cancer has gone through. It is rated 1–5, with 1 the shallowest and 5 the deepest. Breslow thickness is more important than Clark level in assigning a stage to a melanoma.

Margins

This is the area of normal skin around the melanoma. If there is no tumour touching the margins, the pathologist will often describe how close the lesion came to the edge.

Mitotic rate

Mitosis is the process by which one cell divides into two. The pathologist counts the number of actively dividing cells (mitoses) to calculate the average number of mitoses per square millimetre.

Ulceration

The breakdown or loss of the outer layer of skin over the tumour is a sign of rapid tumour growth. The pathologist will determine whether ulceration is present.

Regression

The report will note any lymphocytes (immune cells) within the melanoma and any evidence of tumour regression (destruction).

Staging the melanoma

The test results will help your doctors assign a stage to describe the melanoma. You may also undergo some other diagnostic tests, including blood tests and imaging tests (ultrasound, CT scan or PET scan), to assess whether the melanoma has spread from the original site to other parts of the body. Staging the melanoma helps your health care team decide what treatment is best for you.

Staging melanoma
Stage 0 The melanoma is confined to the outer layer of the skin (also known as in situ melanoma).
Stage 1 The melanoma has not moved beyond the primary site and is 2 mm or less in thickness (may or may not have ulceration).
Stage 2 The melanoma has not moved beyond the primary site and is 2 mm or greater in thickness (may or may not have ulceration).
Stage 3 The melanoma has spread to lymph nodes near the primary site, to nearby skin or to tissues under the skin (subcutaneous).
Stage 4 The melanoma has spread to distant lymph nodes and/or other parts of the body such as the lungs, liver, brain or bone.
Gene mutation testing

Approximately 40% of people with melanoma have a mutation in the BRAF gene and approximately 15% have a mutation in the NRAS gene. These mutations can cause cancer cells to multiply and contribute to the growth of melanomas. If the melanoma is advanced (metastatic), mutation testing of tissue samples is recommended to identify particular genetic mutations that may respond to some medicines. See targeted therapy for more details.

Prognosis

Prognosis means the predicted outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for any doctor to predict the exact course of the disease. Instead, your doctor can give you an idea about common issues that affect people with melanoma.

Melanoma can be treated most effectively in its early stages when it is still confined to the top layer of the skin (epidermis). The deeper a melanoma penetrates into the lower layers of the skin (dermis), the greater the risk that it could spread to nearby lymph nodes or other organs. In recent years, clinical breakthroughs have led to new treatments that continue to improve the prognosis for people with advanced melanoma.

Which health professionals will I see?

Your GP will probably arrange the first tests to assess your symptoms. If these tests do not rule out melanoma, you will usually be referred to a specialist, such as a dermatologist or surgeon, who will arrange further tests and advise you about treatment options.

You may also be cared for by a range of health professionals who specialise in different aspects of your treatment, especially if you have a melanoma with a Breslow thickness greater than 1 mm, or if the melanoma has spread. This is often referred to as a multidisciplinary team (MDT). This team may include some or all of the health professionals described in the table below.

Health professional
 Role
GP (general practitioner) assists with treatment decisions and works with your specialists to provide ongoing care
dermatologist* specialises in the prevention, diagnosis and treatment of skin conditions, including melanoma
general surgeon* performs surgery to remove the melanoma; skin reconstruction; and surgery on the lymph nodes
reconstructive (plastic) surgeon* specialises in complex skin reconstruction techniques
surgical oncologist* specialist cancer surgeon; removes melanomas and conducts more complex surgery on the lymph nodes and other organs
medical oncologist* specialises in treating cancer with drug therapies such as targeted therapy and immunotherapy
radiation oncologist* prescribes and coordinates the course of radiotherapy
specialist nurse administers treatment and provides care and support throughout your treatment
cancer nurse coordinator coordinates your care, liaises with other members of the MDT and supports your family
lymphoedema practitioner educates people about lymphoedema management and provides treatment
counsellor, social worker, psychologist link you to support services, provide emotional support and help manage anxiety and depression
physiotherapist, occupational therapist assist with physical and practical problems
palliative care team specialise in pain and symptom control to maximise wellbeing and improve quality of life

* Specialist doctor

Melanoma units

Some people, particularly if they have a deeper, invasive melanoma, are treated in specialist melanoma units located at hospitals in major cities around Australia. At these centres, specialists in melanoma work together to assess your case and recommend the best treatment.

If you are referred to a melanoma unit or a multidisciplinary team by your GP, you will be able to talk to one or more medical specialists who will answer your questions, and advise you and your GP about your treatment options. The best treatment pathway will depend on the pathology and imaging results.

As well as providing treatment advice, melanoma units are also involved in research studies and may invite you to participate. They may also seek your permission to collect information and tissue and blood samples from you, for use in melanoma research.

People who are at high risk of melanoma are also often asked to take part in research studies, even if they have not been diagnosed with melanoma. See more information on clinical trials.

To find out where a specialist melanoma unit is located, ask your doctor or call Cancer Council 13 11 20.

Most people with melanoma will only require surgery. They will not need to see a medical or radiation oncologist.

Key points

  • A melanoma diagnosis starts with an examination of the suspicious spot or mole, and any other moles on your body.
  • A GP, dermatologist or surgeon can give you a local anaesthetic and remove a spot on your skin for examination by a pathologist. This is called an excision biopsy.
  • The biopsy will provide information about the thickness of the melanoma (Breslow thickness) and how deeply into the skin the cancer cells have grown.
  • Your doctor will feel the nearby lymph nodes to work out if the melanoma has spread to other parts of the body. If necessary, you will have a sentinel lymph node biopsy or fine needle aspiration biopsy to check the lymph nodes for cancer cells.
  • Your doctor will assign a stage to the melanoma based on the test results. This describes the size of the melanoma and whether it has spread.
  • Mutation testing of tissue samples is recommended only in cases of advanced (metastatic) melanoma.
  • Your doctor may talk to you about possible treatments and the expected outcome of the disease (prognosis).
  • There are many health professionals who care for people with melanoma.
  • Some health professionals, such as medical oncologists and radiation oncologists, care for people with a melanoma that is at risk of spreading or has spread (metastatic melanoma).
  • Some people visit specialist melanoma units, which are based in hospitals in major cities around Australia.

Reviewed by: Prof Brendon J Coventry, Associate Professor of Surgery, University of Adelaide, Surgical Oncologist, Royal Adelaide Hospital, and Research Director, Australian Melanoma Research Foundation, SA; A/Prof Victoria Atkinson, Senior Medical Oncologist, Princess Alexandria Hospital and Greenslopes Private Hospital, QLD; Prof Diona Damian, Dermatologist, University of Sydney at Royal Prince Alfred Hospital, and Melanoma Institute Australia, NSW; Sharon Dei Rocini, Consumer; Prof Gerald Fogarty, Director, Radiation Oncology, St Vincent’s Hospital, NSW; Chantal Gebbie, 13 11 20 Consultant, Cancer Council NSW; Miklos Pohl OAM, Plastic and Reconstructive Surgeon, Peter MacCallum Cancer Centre and Epworth Healthcare, VIC; Julie Teraci, Clinical Nurse Consultant, Western Australian Melanoma Advisory Service, St John of God Subiaco Hospital, WA.
Updated: 01 Jan, 2017