Uncontrolled growth of melanocytes (pigment cells) resulting in skin cancer.
Australia has the highest rate of melanoma in the world. Arising from normal-looking skin, inside freckles or moles, or occasionally in the genitals, eye or other internal sites, melanoma is a type of skin cancer caused by the overproduction of pigment cells (melanocytes). This uncontrolled growth can become cancerous and invade deeper layers of the skin and potentially other parts of the body.
The growth of pigment cells (melanocytes) can result in the normal non-cancerous cell production of moles and freckles. The cancerous growth of these cells is the origin of melanoma. Having many moles and freckles can increase your risk of developing melanoma.
Melanoma can be categorised as in situ, invasive or metastatic. If a tumour is in situ is has been restricted and removed while in the outer layer of the skin (epidermis), it has not spread. Invasive growth indicates the melanoma has expanded into the deeper levels of the skin (dermis). Once a tumour has spread into other tissues, it is classified as metastatic.
Occurring anywhere in the body, melanoma is caused by overexposure to ultraviolet (UV) radiation through the sun. There are different types of melanoma a person can have, including but not limited to superficial spreading, nodular, lentigo maligna and acral lentiginous. Each type varies in severity.
Extensive unprotected sun exposure and familial history (two or more immediate relatives with melanoma history) are known to be increased risks. Other key risk factors include;
A large number of moles (naevi)
Previous history of melanoma
White skin that burns easily (see the Fitzpatrick skin chart)
Multiple irregular moles
How is Melanoma Diagnosed?
Early diagnosis is the key to surviving melanoma. Regular skin checks with a dermatologist and self-checking at home (following Cancer Council Australia's self-check guide) are the ideal preventative methods. Following the ABCDE of assessing your skin can help identify any suspicious lesions for further examination by a medical professional.
A complete and thorough skin examination by a medical professional is the first step in the diagnosis process. If your doctor flags any areas of concern, they will biopsy the spot for further analysis. A doctor will identify a suspicious lesion because of its clinical features or its history of change if it has been monitored in the past.
A biopsy is a procedure where the doctor will use a scalpel under local anaesthetic to remove the lesion and a small amount of surrounding healthy tissue for testing. Usually, the entirety of the suspicious spot will be removed to ensure an accurate diagnosis. The biopsy will be reviewed by a pathologist and diagnosed, your dermatologist will give you the results.
A followup appointment is required for the removal of stitches and if diagnosed with melanoma, to discuss a further treatment plan.
Melanoma staging dictates the severity of cancer.
Your diagnosis will include Breslow thickness and Clark level, which help determine the overall stage of your melanoma. Early-stage Melanoma is treated with surgical excision of the affected area. Melanoma In situ will be completed treated by excision. Stage 1-2 localised tumours are mostly treated with surgery. The risk for tumours 0.75–1 mm thick is about 5% to metastasize; this increases with thickness.
Stage 3-4, when there is regional or lymph node involvement, treatment may include removing lymph nodes and further adjunct treatment.
Ongoing regular skin checks are required after a melanoma diagnosis to monitor reoccurrence. A treatment plan will be developed with your dermatologist and other specialists, depending on cancer advancement.