Melanomas are a type of cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs that develop from melanocytes, which are the cellsthe basic structural and functional unit of all living things that produce pigment, generally in the skin. However, they can also develop in the eye and possibly other parts of the body. Cutaneous melanomaa type of cancer that develops from melanocytes, which are the cells that produce pigment generally in the skin (but can develop in other areas of the body) refers to melanomas of the skin, and is one of the most common types of skin cancer.
The skin is the largest organ in our bodies that protect us from injury, loss of bodily fluids and help regulate body temperature. There are three layers of the skin: epidermis (top layer), dermis (middle layer) and hypodermis (bottom layer). The epidermis is the water-resistant outer layer of the skin that acts as the body’s first line of defence. It contains squamous cells (upper layer of the epidermis), basal cells (lower layer of epidermis) and melanocytes. The dermis contains the skin’s connective tissues, as well as hair follicles, sweat glands, bloodthe red bodily fluid that transports oxygen and other nutrients around the body vessels, lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid and nerves. The hypodermis, also known as subcutaneousunder the skin tissuea group of cells that work together to perform a function layer, stores fat (adipose cells), and also contains connective tissue, blood vessels and nerve cells.
Melanoma is most common in males; however, anyone can develop this disease at any age.
Types of Cutaneous Melanoma
There are several types of cutaneous melanoma, which are classified by the by their appearance on the skin.
Superficial Spreading Melanoma
Superficial spreading melanoma is the most common type of melanoma, and is generally found in people under 40. This type of cancer often appears as a new black or brown spot on the skin, or as a spot, freckle or mole that changes in appearance (e.g., size, shape, colour etc.). These cancers can appear anywhere on the body, but is most commonly found on the trunk of the body. Superficial spreading melanomas are often slow growing, but can become aggressive when it grows into the dermis layer of the skin.
Nodular Melanoma
Nodular melanoma is a less common subtype of melanoma that generally affects people over 65. These melanomas often appear as pink, red, brown or black lumps (or nodules) on the skin. Nodular melanomas are usually found on skin that has been damaged by the sun, especially on the head and neck, and can be aggressive.
Lentigo Malinga Melanoma
Lentigo Malinga melanomas are a less common subtype of melanoma that mainly affects people over 40. It often occurs as a large, coloured spot on the skin (letting Malinga) on sun-damaged skin, usually on the face, ears, and neck. This subtype is often very slow growing, and may progress over many years before spreading into the dermis layer of the skin.
Acral Lentiginous Melanoma
Acral lentiginous melanomas are a rare form of melanoma that generally affects people over 40. They are often light in colour or colourless, so they may be mistaken for a bruise or a skin stain. Acral lentiginous melanomas are commonly found in the palms of your hands, the soles of your feet or under your finger/toenails. This subtype of melanoma is often slow growing, but may become aggressive when it grows into the dermis layer of the skin.
Desmoplastic Melanoma
Desmoplastic melanomas are a rare subtype of melanoma that generally affects people over 60. This type of cancer often appears as a colourless, firm, lump on the skin, and can be difficult to diagnose. They are mainly found on sun-damaged skin, particularly on the head and neck. Desmoplastic melanomas are the slowest growing subtype of melanoma; however, it is usually diagnosed later than other subtypes.
Nail Unit Melanoma
Nail unit melanoma is a rare variant of cutaneous melanoma which develops underneath the fingernail. It most commonly develops in the thumb or the big toe, and is most common in people between the ages of 50-70. For more information on nail unit melanoma, please refer to the Rare Cancers Australia Melanoma (Nail Unit) page.
Treatment
If cutaneous melanoma is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancer cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumoura tissue mass that forms from groups of unhealthy cells) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for cutaneous melanomas may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, potentially including:
- Wide local excisionremoval of cancerous tissue and a margin of healthy tissue around it to prevent cancer recurrence.
- Lymphadenectomysurgical removal of lymph node(s).
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Immunotherapya treatment that uses a person's immune system to fight cancer.
- Targeted therapymedication that targets specific molecular features of cancer cells.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
The biggest riskthe possibility that something bad will happen factor for cutaneous melanomas is exposure to ultra-violet (UV) radiation from the sun or other sources, such solariums (sun beds). Other potential risk factors include:
- A history of childhood tanning and/or sunburn.
- Regular short and intense periods of UV radiation.
- Having over 50 moles on the body, or over 10 on the upper arms.
- Having a lot of unusual moles.
- Being immunosuppressed.
- Having a family and/or personal history of skin cancer.
- Physical appearance, including having:
- Fair skin.
- Lots of freckles.
- Light eye colour (usually blue or green).
- Light hair colour (such as blonde or red).
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
Cutaneous melanomas often appear as unusual moles, freckles, or spots. However, their appearances can vary greatly depending on cancer type, age of the patient and other individual factors. Generally, most types of cutaneous melanomas have characteristics that can be described by the Glasglow 7-point checklist and/or the ABCDEFG of melanoma.
Glasglow 7-point checklist
The Glasglow 7-point checklist is composed of major and minor features of melanomas.
Major features
Major features include:
- Changes in shape, potentially including:
- Increased height.
- Ragged edges.
- Scalloped or notched shape.
- Becoming asymmetrical.
- Becoming scaly.
- Irregular shape, potentially including:
- Increased height.
- Ragged edges.
- Scalloped or notched shape.
- Being asymmetrical.
- Being scaly.
- Irregular colour, potentially including:
- Becoming blotchy.
- Brown, black, red, white, light grey or the colour of your skin.
Minor features
Minor features include:
- Diameter over seven millimetres.
- Inflammation.
- Oozing or bleeding.
- Change in sensation (e.g., becoming painful, elevated, itchy or a new lump).
ABCDEFG of Melanoma
The symptoms of a cutaneous melanoma can also be categorised by this method, which evaluates different features of the potential cancer.
- A: Asymmetry of shape and/or colour.
- B: Border irregularity.
- C: Colour variation and changes.
- D: Diameter.
- E: Elevated or evolving (becoming larger, changing in appearance etc.).
- F: Firm.
- G: Growing.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis
If your doctor suspects you have a melanoma, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imagingtests that create detailed images of areas inside the body tests (if the cancer is thought to have spread beyond the skin), potentially including:
- X-raya type of medical imaging that uses x-ray beams to create detailed images of the body .
- Ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body .
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
