Dr Julie Smith - Dermatologist
Private Service, Dermatology
New Zealand has a very high rate of skin cancer, when compared to other countries. The most common forms of skin cancer usually appear on areas of skin that have been over-exposed to the sun.
Risk factors for developing skin cancer are: prolonged exposure to the sun; people with fair skin; and possibly over-exposure to UV light from sun beds.
There are three main types of skin cancers: basal cell carcinoma, squamous cell carcinoma and malignant melanoma.
Basal Cell Carcinoma (BCC)
This is the most common type and is found on skin surfaces that are exposed to sun. A BCC remains localised and does not usually spread to other areas of the body. Sometimes BCC’s can ulcerate and scab so it is important not to mistake it for a sore.
BCCs occur more commonly on the face, back of hands and back. They appear usually as small, red lumps that don’t heal and sometimes bleed or become itchy. They have the tendency to change in size and sometimes in colour.
Often a BCC can be diagnosed just by its appearance. In other cases it will be removed totally and sent for examination and diagnosis, or a biopsy may be taken and just a sample sent for diagnosis.
Removal of a BCC will require an appointment with a doctor or surgeon. It will be termed minor surgery and will require a local anaesthetic (numbing of the area) and possibly some stitches. A very small number of BCCs will require a general anaesthetic (you will sleep through the operation) for removal.
Squamous Cell Carcinoma (SCC)
This type of skin cancer also affects areas of the skin that have exposure to the sun. The most common area is the face, but an SCC can also affect other parts of the body and can spread to other parts of the body. The spreading (metastasising) can potentially be fatal if not successfully treated.
A SCC usually begins as a keratosis that looks like an area of thickened scaly skin, it may then develop into a raised, hard lump which enlarges. SCCs can sometimes be painful. Often the edges are irregular and it can appear wart like, the colour can be reddish brown. Sometimes it can appear like a recurring ulcer that does not heal.
All SCCs will need to be removed, because of their potential for spread. The removal and diagnosis is the same as for a BCC.
This is the most serious form of skin cancer. It can spread to other parts of the body and people can die from this disease.
A melanoma usually starts as a pigmented growth on normal skin. They often, but not always, occur on areas that have high sun exposure. In some cases, a melanoma may develop from existing pigmented moles.
What to look for:
- an existing mole that changes colour (it may be black, dark blue or even red and white)
- the colour pigment may be uneven
- the edges of the mole/freckle may be irregular and have a spreading edge
- the surface of the mole/freckle may be flaky/crusted and raised
- sudden growth of an existing or new mole/freckle
- inflammation and or itchiness surrounding an existing or new mole/freckle.
It is important that any suspect moles or freckles are checked by a GP or a dermatologist. The sooner a melanoma is treated, there is less chance of it spreading.
A biopsy or removal will be carried out depending on the size of the cancer. Tissue samples will be sent for examination, as this will aid in diagnosis and help determine the type of treatment required. If the melanoma has spread more surgery may be required to take more of the affected skin. Samples from lymph nodes that are near to the cancer may be tested for spread, then chemotherapy or radiotherapy may be required to treat this spread.
Once a melanoma has been diagnosed, a patient may be referred to an oncologist (a doctor who specialises in cancer).
A melanoma that is in the early stages can be treated more successfully and cure rates are much higher than one that has spread.