ABOUT SKIN CANCER
Did you know?
- New Zealand and Australia have the highest rates of melanoma in the world
- Approximately 50% of all Kiwis will get a skin cancer in their lifetime
- 80 % of all new cancers diagnosed in New Zealand are skin cancers
- Melanoma is the leading cancer for males aged 25 to 44 years old and the second most common for females of the same age.
- Melanoma is the fourth most common life-threatening cancer in New Zealand for all ages combined
- Melanoma is the most serious of all skin cancers. However it is by no means the most prevalent and only forms less that 5% of all skin cancers.
- From the age of 50, the rate of all skin cancers increase significantly with each decade.
What is skin cancer?
Like all body tissues, the skin is made of tiny ‘building blocks’ called cells. These cells can sometimes become cancerous when they have been damaged, for example, by ultraviolet (UV) radiation. Skin cancers are named after the type of cell they begin to grow from. The three most common types of skin cancer are basal cell cancer, squamous cell cancer and melanoma.
Basal and squamous cell cancers
Two thirds of skin cancers can be classified as either basal cell or squamous cell cancers. Basal cell cancers (BCCs) are extremely prevalent in New Zealand and present as tumours which tend to grow and destroy surrounding tissue. They are routinely cured by modern treatments. Squamous cell cancers frequently present as scaly patches or non-healing areas. If not treated early, they do have the potential to spread.
Regular self-examination, as well as a full body skin check by a professionally trained skin cancer doctor in dermoscopy, is the best defence against skin cancer. If detected early the cancers are smaller, thinner and the chance of definitive cure is much higher than if diagnosed late.
What is melanoma?
A melanoma is a tumour that develops from melanocytes (pigment cells). Melanoma most commonly occurs in the skin on parts of the body that have been sunburnt, but it can appear in skin anywhere on the body.
Melanomas usually begin as a flat, coloured spot that changes in size, shape, or colour or becomes raised over months. A less common type of melanoma - called nodular melanoma - is not flat and is raised from the start. These melanomas grow quickly, are uniform in colour or may have no colour. If detected, when they are thin and at an early stage, most melanomas are curable.
Melanoma can start in parts of the body other than the skin, but this is rare. The other parts of the body that can be affected are:
- The eye (ocular melanoma)
- The mouth, vulva or vagina (mucosal melanoma)
- Under fingernails or toenails (subungual melanoma).
What to look for
The first sign of a melanoma is usually the appearance of a new spot or a change in an existing freckle or mole:
- The change may be in size, shape and/or colour
- The change is normally noticed over several weeks or months rather than days
- A normal freckle or mole usually has an even colour and a smooth edge
- A melanoma often has an irregular edge or surface. It may be spotted with brown, black, blue, red, white and/or light grey.
- A freckle or mole that itches or bleeds by itself is sometimes, but not always, a melanoma
- A freckle or mole that becomes larger or irregular in shape may be a melanoma. It is quite normal for new moles to appear and change during childhood and early adulthood.
Risk factors for melanoma include
- Fair skin and red or fair hair
- One or more severe sunburns, especially in childhood and adolescence
- Use of sunbeds, particularly by young people
High-risk factors include
- Previous skin cancers including melanoma
- A family history of melanoma in a first degree relative: parent, brother, sister or child
- Large, irregularly shaped and unevenly coloured moles called atypical or dysplastic naevi
- A large number of moles
Causes of melanoma
Too much sun, especially sunburn, can cause melanoma. Each time your unprotected skin is exposed to the sun’s UV radiation or other sources of UV radiation such as sunbeds, the UV radiation causes changes to the structure of the cells. Overexposure to UV radiation causes the skin to become permanently damaged. The damage worsens with more UV radiation. The most important years for sun protection are during childhood and early adult years. Exposure to UV radiation during these years greatly increases the chance of getting melanoma later in life.
Protecting yourself from melanoma
Apply sunscreen (SPF 30) every day of the year. Reapply regularly if swimming or undertaking physical exercise causing sweating. Your best protection is staying out of the sun. If not possible, wear long sleeves, hats and aim to stay in the shade when you can.
MoleMan recommends the following websites for skin cancer related information:
The Melanoma Network of NZ
The Melanoma Foundation of NZ
Cancer Society NZ
Skin Cancer College Australasia