Melanoma is a potentially serious type of skin cancer which is said to affect about 1 in 15 New Zealanders in their lifetime. The incidence of this cancer in New Zealand and Australia is among the highest in the world.

Risk factors include sun exposure, blistering sunburn, and fair skin. Previous melanoma and a family history of melanoma are also risk factors.

Most melanomas grow by initially spreading out in the outer layer of skin before invading tissues under the skin. Once an invasive melanoma has developed there is a risk of spread to lymph nodes, or more distant sites in the body ("metastases").

Any pigmented lesion, including freckles or moles, showing changes such as altered pigmentation, increase in size, irregularity, nodularity or ulceration, should be checked by an experienced doctor.

If there is any doubt, excision may be required to determine the diagnosis. If a melanoma is confirmed, then other investigations (such as a CT scan or PET scan) may be required to determine if any other treatment is needed.