Diagnosing melanoma

Thursday 1 January, 2015

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


Physical examination

Usually you begin by seeing a doctor to have the suspicious spot or mole, and any other moles on your body examined. The doctor may use a magnifying instrument, called a dermascope, to see the spot clearly and will ask if you or your family have a history of melanoma.

Removing the mole (excision biopsy)

If the doctor suspects that a spot on your skin may be melanoma, the usual procedure is to have a biopsy. This is generally a quick and simple procedure. Your GP may do it, or you may be referred to a dermatologist or plastic surgeon.

You will have a local anaesthetic injected into the area near the mole. The doctor will use a scalpel to remove the spot and a small area of tissue around it. A stitch or stitches will be used to close up the wound. The tissue sample will be sent to a laboratory for examination under a microscope by a tissue specialist (histopathologist).

It is recommended that the entire mole is removed rather than a small biopsy due to the potential of an inaccurate and misleading diagnosis.

Results are usually ready in about a week, and a follow-up appointment may be arranged. This waiting period may be an anxious time. Call Cancer Council 13 11 20 for support or it may help to talk things over with a close friend, relative or health professional. If the mole contains cancerous cells you will need further surgery, such as a wide local excision.

Pathology report

If you have melanoma, the pathologist will prepare a report that provides 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. Melanomas are classified into four categories:

  • less than 1mm (most melanomas are this category)
  • 1–2 mm
  • 2.1–4 mm
  • greater than 4 mm
Clark level

This describes how deeply the cancer has gone through into layers of the skin. It is rated 1–5, with 1 being the most shallow and 5 the deepest. A low Clark level means the cancer is close to the skin’s surface (more superficial); a high level means the cancer has penetrated more deeply into the skin. It is important not to confuse the level of a melanoma with the stage.

Margins

This is the edge of an excision specimen. If there is no tumour touching the margins, the pathologist will describe how close the lesion came to the edge.

Mitotic rate

Mitosis is the process by which one mature cell divides into two identical cells. The pathologist counts the number of actively dividing cells (mitoses) that they see. Averaging this number gives the mitotic count, which is stated as the number of mitoses per square millimetre.

Ulceration

The breakdown or loss of the epidermis. Ulceration is determined by the pathologist when the specimen is examined under a microscope.

Checking the lymph nodes

Once the melanoma has been diagnosed, the doctor will check the nearby lymph nodes to see if the cancer has spread. This provides more accurate information about the stage of the melanoma.

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

To check if the melanoma has spread to a lymph node or several lymph nodes, your doctor may recommend that you have a fine needle aspiration biopsy or a sentinel node biopsy.

Fine needle aspiration biopsy

The doctor takes a sample of cells by inserting a needle into a suspicious node. This tissue is examined under a microscope to see if it contains cancer cells.

Sentinel node biopsy

The sentinel lymph node drains fluid from the area where the melanoma developed. It is located by injecting a small amount of radioactive fluid into the area where the melanoma was removed. The radioactive fluid is not harmful. This procedure, called lymphoscintigraphy, is done to see which node has absorbed the injected fluid first. This is the sentinel node, and it is then removed in a small operation and checked for cancer cells.

If cancer cells are found, the remaining nodes in the area are also removed. This is to try to stop cancer coming back in the same area and to assess the risk of the cancer spreading to other parts of the body.

A sentinel lymph node biopsy can provide information that helps predict the risk of melanoma spread in the future, and can help your doctor plan your treatment. It may also allow you to access new trials to test future cancer treatments. The risk of having melanoma in the lymphatics increases with the Breslow thickness of the primary melanoma and is very low for thin melanomas. For this reason, sentinel node biopsy will only be offered to patients if the Breslow thickness of their melanoma is over 1 mm or they have a Clark level of 4.

Staging the melanoma

Staging determines whether the melanoma has spread from the original site to other parts of the body. This is based on diagnostic tests, which could include blood tests, X-rays, CT scans, MRI or PET scans. Staging the melanoma helps your health care team decide what treatment is best for you.

Staging melanoma
Stage 1 The melanoma has not moved beyond the primary site. This is called localised cancer.
Stage 2 The melanoma has spread to nearby skin and subcutaneous tissues.
Stage 3 The melanoma has spread to lymph nodes near the primary site.
Stage 4 The melanoma has spread to other parts of the body.

Prognosis

Prognosis means the expected 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. The type of melanoma you have, how well you respond to treatment, and other factors such as age and medical history are all important in assessing your prognosis.

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 skin, the greater the risk that it may spread to draining lymph nodes or other organs.

In Australia, more than 90% of people with melanoma are treated successfully with surgery. With early detection and treatment, the outlook has steadily improved over the past 50 years.

Which health professionals will I see?

You may be cared for by a range of health professionals, called a multidisciplinary team, 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. Ideally, all your tests and treatment will be available at your hospital, although this may not always be possible.

This team may include some or all of the health professionals listed below.

Health professionals for people with early stage melanoma
dermatologist specialises in the diagnosis and treatment of skin cancers and other skin disorders
histopathologist examines tissue to diagnose cancer
surgeon performs operations to remove the melanoma
reconstructive (plastic) surgeon specialises in surgery to reconstruct the appearance of the body
specialist nurses support you throughout your diagnosis and treatment
GP (general practitioner) assists you in obtaining practical and emotional support and works in partnership with your specialists in providing ongoing care

Additional health professionals for people with advanced melanoma
radiologist specialises in reading medical imaging tests such as x-rays, CT and MRI scans
radiation therapist plans and delivers radiotherapy treatment
lymphoedema therapist educates people about lymphoedema management and provides treatment if lymphoedema occurs
medical oncologist prescribes and coordinates the course of treatment that may include targeted therapies, immunotherapy and chemotherapy
radiation oncologist prescribes and coordinates the course of radiotherapy
cancer care coordinators support and assist you through all stages of your treatment
dietitian recommends an eating plan for you to follow while you are in treatment and recovery
social worker, counsellor, psychologist, psychiatrist link you to support services, provide emotional support, assist with emotional concerns, and help manage depression and anxiety
physiotherapist and occupational therapist assist with physical and practical problems, including restoring range of movement after surgery and managing lymphoedema
palliative care team offer a range of services for people with advanced cancer to improve their quality of life and ensure their physical, practical, emotional and spiritual needs are met

Melanoma units

Some people are diagnosed and treated in specialist melanoma units available 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, a histopathologist may review your biopsy results and a radiologist may review your imaging. Based on these results, a consensus opinion will be reached regarding your treatment. 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.

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 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 histopathologist. 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 (Clark level).
  • 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 fine needle biopsy or sentinel node biopsy to check the lymph nodes for cancer cells.
  • 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 major cities around Australia.

Reviewed by:Prof Bryan Burmeister, Director of Radiation Oncology, Princess Alexandra Hospital, QLD; Dr Victoria Atkinson, Senior Medical Oncologist, Division of Cancer Services, Princess Alexandra Hospital, QLD; Assoc Prof John Kelly, Head of Victorian Melanoma Service VIC; Dr Mark Hanikeri, Director WA Melanoma Advisory Service, Plastic and Reconstructive Surgeon, WA Plastic Surgery Centre WA; Lydia Visintin, Clinical Nurse Consultant, Melanoma Institute Australia NSW; Carol Hargreaves, 13 11 20 consultant, Cancer Council NSW; Julie Fraser, Peer Support Volunteer, Cancer Council QLD ; Susanna Cramb, Viertel Cancer Research Centre, Cancer Council QLD.
Updated: 01 Jan, 2015