Non Melanoma and the Types of Non Melanomas
Skin cancers are generally divided into the serious but less common malignant melanoma which usually develops from moles on the body and non-melanomas which occur because of exposure to the sun.
Non melanomas are divided into two types - basal cell cancer and squamous cell cancer.
Both types are common and curable but in a very small number of people (about 1%) if the cancer is left untreated it can spread (metastasise) to other parts of the body. The result of this can be fatal.
Basal cell cancer (BCC)
Basal cell cancer is the most common form of malignant skin cancer, accounting for around 75% of all non-melanomas. It is rare in people with darker skins because they have far more of the protective pigment melanin.
The name comes from the fact that this type of cancer develops in the basal cells of the skin which are found in the deepest area of the epidermis (the top layer of the skin). These cells become damaged from frequent exposure to the sun, making them more susceptible to cancer cells.
Most BBCs are very slow developing and are common in people over 60 who may have spent a lifetime being exposed to the sun. However this form of skin cancer is becoming prevalent in younger people, possibly because of frequent sunburn episodes as children and the fact that more of us now take holidays in the sun.
Typically the cancer appears in areas that are exposed to the sun such as the face, hands or neck, although it can develop on the lower legs or back. It often appears as small pink or red pearly dome shaped lumps and can take many months to grow even to a small size. People can have more than one BCC at any time. If basal cell cancer is untreated it can develop into what is known as a rodent ulcer which can spread and eat away at the other body tissues surrounding it.
Squamous Cell Cancer (SCC)
This is the second most common type of skin cancer, accounting for about one in five of all diagnosed skin cancers. Again it affects white, fair haired, fair skinned people and is very uncommon, although not unknown, in those with darker skins.
Like BCC it occurs in the epidermis, this time in the very top layer, and as its name suggests, in the squamous cells. And again it is common in the over 60s.
Over exposure to the sun is generally the cause which is why these cancers occur on the main sun exposed areas such as the nose, lower lips, ears, hands and head. They develop as lumps, thickened, crusty or scaly skin and may even resemble warts. They can occasionally ulcerate or bleed.
Squamous cell cancer can also occur on areas of skin that have been damaged because of burns, scars or radiotherapy.
SCC can be very disfiguring if it is untreated as it can grow larger and deeper and begin to eat away at the surrounding skin tissue.