Melanoma


Diagnosing melanoma

Tuesday 1 January, 2019

Physical examination

If you notice any changes to your skin, your doctor will examine you, looking carefully at any spots you have identified as changed or suspicious. The doctor will ask if you or your family have a history of melanoma. Using a handheld magnifying instrument called a dermoscope, the doctor will examine the spot more closely and consider the criteria known as "ABCDE".

ABCDE signs of melanoma
Asymmetry Are the halves of each mole different?
Border Are the edges uneven, 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 types of melanoma, such as nodular and desmoplastic melanomas, don’t fit the “ABCDE” criteria, so your doctor may also assess whether the spot is elevated, firm or growing.

Removing the mole (excision biopsy)

If the doctor suspects that a spot on your skin may be melanoma, the whole spot is removed (excision biopsy) for examination by a tissue specialist (pathologist).

This is generally a simple procedure done in your doctor's office. Your GP may do it, or you may be referred to a dermatologist or surgeon.

For this procedure, you will have an injection of local anaesthetic to numb the area. The doctor will use a scalpel to remove the spot and a small amount (2 mm margin) 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 work out if it contains melanoma cells. Results are usually ready within a week.

See information about what the pathology results mean.

You'll have a follow-up appointment to check the wound and remove the stitches.

If a diagnosis of melanoma is confirmed, you will probably need further surgery, such as a wide local excision.

Checking 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. To test whether the melanoma has spread, your doctor may recommend that you have a fine needle biopsy or a sentinel lymph node biopsy.

Fine needle biopsy

A thin needle is used to take a sample of cells from an enlarged lymph node. Sometimes an ultrasound helps guide the needle into place.

The sample is then examined under a microscope to see if it contains cancer cells.

Sentinel lymph node biopsy

If the Breslow thickness (see below) of the melanoma is over 1 mm or sometimes for people with melanoma between 0.8 mm to 1 mm, you may be offered a sentinel lymph node biopsy.

This biopsy finds and removes the first lymph node/s that the melanoma would be likely to spread to (the sentinel node/s). It is usually done at the same time as the wide local excision.

A sentinel lymph node biopsy can provide information that helps predict the risk of melanoma spreading to other parts of the body. This information can help your doctor plan your treatment.

It may also allow you to access new clinical trials.

To find the sentinel node/s, a small amount of radioactive dye is injected into the area where the melanoma was found.

The surgeon removes the node that absorbs the injected fluid to check for cancer cells.

If they are found in the sentinel lymph node, further tests such as ultrasound, CT or PET scans may be done during follow-up and systemic treatment may be offered.

Pathology report

If you have melanoma, the report from the pathologist will provide your treatment team with information to help determine the stage, plan treatment, and work out your prognosis.

You can ask your doctor for a copy of the results, and discuss the results with them. The following factors may be included:

Breslow thickness

This is a measure of the thickness of the tumour in millimetres to its deepest point in the skin.

The thicker a melanoma, the more likely it could return (recur) or spread to other parts of the body.

Clark level

This describes how many layers of skin the tumour has gone through. It is rated I–V, with I the shallowest and V the deepest.

Breslow thickness is much more important than Clark level in assigning a stage to a melanoma.

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.

Ulceration

The breakdown or loss of the outer layer of skin over the tumour is a sign of rapid tumour growth.

Mitotic rate

Mitosis is the process by which one cell divides into two. The pathologist counts the number of actively dividing cells to calculate how quickly the melanoma cells are dividing.

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 abnormal tissue (lesion) was from the edge.

Regression

The report will note any lymphocytes (immune cells) within the melanoma and any evidence of whether some melanoma cells have been destroyed by the immune system and replaced with scar tissue.

Staging melanoma

The test results will help your doctors assign a stage to describe the melanoma.

You may also have some other diagnostic tests, including blood tests and imaging tests (ultrasound, CT scan or PET scan), to work out whether the melanoma has spread from the primary site to other parts of the body.

Staging the melanoma helps your health care team recommend the most appropriate treatment for you.

Staging melanoma
Stage 0 (in situ) The melanoma is confined to the top, outer layer of the skin.
Stage I The melanoma has not moved beyond the primary site and is 2 mm or less in thickness (may or may not have ulceration).
Stage II The melanoma has not moved beyond the primary site and is greater than 1 mm and ulcerated or greater than 2 mm in thickness (may or may not have ulceration).
Stage III The melanoma has spread to lymph nodes near the primary site, to nearby skin or to tissues under the skin (subcutaneous).
Stage IV The melanoma has spread to distant skin and/or other parts of the body such as the lungs, liver, brain, bone or distant lymph nodes.

Stages 0, I and II are called early melanoma, while stage III is referred to as regional melanoma. Stage IV melanoma has spread to other parts of the body and is called advanced or metastatic.

Gene mutation testing

If the melanoma has spread (stage III or IV), further tests can help work out whether you have a particular gene change (mutation) that may be causing the cancer cells to multiply and grow.

These genetic mutations are due to changes in cancer cells – they are not the same thing as genes passed through families.

Approximately 40% of people with melanoma have a mutation in the BRAF gene and approximately 15% have a mutation in the NRAS gene. C-KIT is a rare mutation affecting less than 4% of people.

Genetic tests can be done on the sample removed during surgery.

The test results will help doctors decide whether you are offered immunotherapy or targeted therapy.

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 discuss any concerns you have.

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 layer of the skin (dermis), the greater the risk that it could spread to nearby lymph nodes or other organs.

In recent years, clinical trials have led to new treatments that continue to improve the prognosis for people with melanoma that has spread from the primary site (advanced melanoma).

What to expect

To help people with melanoma receive the best care possible, we have developed an optimal cancer care pathway. View the guide to make sure you get the best care and support at each stage.

Key points about diagnosing melanoma

Main tests

Tests to diagnose melanoma include:

  • examination of the suspicious spot or mole, and any other moles on your body
  • removing 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.

Other tests

Your doctor will feel the nearby lymph nodes to work out if the melanoma has spread to other parts of the body.

To check the lymph nodes for cancer cells, you may have a:

  • fine needle biopsy
  • sentinel lymph node biopsy.

Staging and prognosis

The stage shows how far the melanoma has spread. Early melanoma is stages 0–II.

Regional melanoma is stage III. If the melanoma has spread, it is considered stage IV.

In these cases, hene mutation testing of tissue samples is recommended.

Your doctor may talk to you about the prognosis, which is the expected outcome for your type and stage of cancer.

Expert content reviewers:

A/Prof Victoria Atkinson, Senior Staff Specialist, Princess Alexandra Hospital, Visiting Medical Oncologist, Greenslopes Private Hospital, and The University of Queensland Clinical School of Medicine, QLD; Adjunct Prof John Kelly AM, Consultant Dermatologist, Victorian Melanoma Service, and Department of Medicine at Alfred Health, Monash University, VIC; Dr Alex Chamberlain, Dermatologist, Glenferrie Dermatology, Victorian Melanoma Service and Monash Univeristy, VIC; Alison Button-Sloan, Melanoma Patients Australia; Peter Cagney, Consumer; Prof Brendon J Coventry, Associate Professor of Surgery, The University of Adelaide, Surgical Oncologist, Royal Adelaide Hospital, and Research Director, Australian Melanoma Research Foundation, SA; Dr David Gyorki, Consultant Surgical Oncologist, Peter MacCallum Cancer Centre, VIC; Liz King, Skin Cancer Prevention Manager, Cancer Council NSW; Shannon Jones, SunSmart Health Professionals Coordinator, Cancer Council Victoria; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Prof Richard Scolyer, Senior Staff Specialist, Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Co-Medical Director, Melanoma Institute Australia and Clinical Professor, The University of Sydney, NSW; Heather Walker, Chair, Cancer Council National Skin Cancer Committee, Cancer Council Australia.

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