Basal cell carcinoma
Basal cell carcinomas are the most common and the least dangerous form of skin cancer. They account for about three-quarters of all skin cancer cases and are particularly common in New Zealand and Australia. These cancers almost never spread to other parts of the body (metastasise). However, if left untreated, they can cause damage by growing very large by invading surrounding tissue.
Basal cell carcinoma on face
Two basal cell carcinomas. On left: side view of raw wound around and partially in the ear. On right: a patch of scaly skin on forehead.
Basal cell carcinomas are growths (tumours) that occur in the basal cells of the epidermis (the top-most layer) of the skin. Basal cells are found in the deepest layers (the base) of the epidermis.
Cross section of skin
Diagram showing a cross section of skin on the left and on the right a cross section showing the cell types.
There are several different types of basal cell carcinoma, and each type looks different. Sometimes they look like non-cancerous skin conditions such as eczema or psoriasis.
The most common forms are:
a pink or red patch of scaly skin, which can be mistaken for patches of dermatitis or eczema
an open sore that doesn’t heal
a shiny bump that is pearly or translucent
a pink growth
a shiny and tight scar-like area.
The Sun is responsible for over 90% of all skin cancers including basal cell carcinomas, so they are usually (but not always) found on areas of the body that are exposed to the Sun such as the face, ears, back of the hands, arms and shoulders. Research shows that it is specifically the UVB rays that cause basal cell carcinomas.
Are basal cell carcinomas life-threatening?
Basal cell carcinomas do not often cause death. This is because they are not usually invasive – they very rarely spread to other parts of the body – so it is extremely rare for basal cell carcinomas to affect the lymph nodes or blood. However, if it is not treated, it can grow very large, be very, very disfiguring and can totally destroy local tissue, for example, ears, noses, eyelids, lips, nerves, cartilage or bone.
Basal cell carcinoma
Red sore form of basal cell carcinoma.
Because basal cell carcinomas are not invasive metastasising cancers, they are not required to be reported and registered by doctors. That also means that they are not included in our national cancer statistics. It is estimated that there are between 45,000 (confirmed by laboratory tests) and 70,000 instances of basal cell carcinoma each year in New Zealand.
How is basal cell carcinoma treated?
Treatment varies depending on the size, depth and location. The most common treatment is surgical removal – the earlier the better. Other treatment options include scraping out, freezing with liquid nitrogen (cryotherapy) and radiation. Smaller and early-stage basal cell carcinomas can be treated with topical creams.
Related content
Learn about other skin cancers – Melanoma and Squamous cell carcinoma.
Find out more about skin cancer, why New Zealand skin cancer rates are so high, some of the risk factors and how skin cancer is diagnosed and treated. that contribute to skin cancer.
Activity ideas
The face of melanoma is an activity that looks at lifestyle factors that contribute to skin cancer.
To tie in sun safety with skin cancer learning take a look at the activities Investigating sunscreens, Investigating UV intensity and UV bead items.
Useful link
The Skin Cancer Foundation (USA) website has descriptions and images of different skin cancers including basal cell carcinoma.
