Basal cell carcinoma is the most common yet least dangerous type of skin cancer. It accounts for approximately 75% of all skin cancer cases in New Zealand. There is a range of characteristic symptoms of basal cell carcinomas and effective treatment options that, if the disease is identified early, can have excellent outcomes.
Skin cancers are named after the type of skin cells from which they originate. Basal cell carcinomas (BCC) arise from basal cells that are located in the lower layers of the skin (in contrast to melanoma skin cancers
that arise in the skin's pigment-producing cells, called melanocytes).
People with BCCs are likely to develop further BCCs and are at increased risk of other skin cancers, including melanoma. It most commonly occurs in people with fair complexions - particularly those who have had considerable exposure to the sun or have had repeated sunburn. It is also thought that the tendency to develop BCCs may run in families.
It is exceedingly rare for BCCs to affect the lymph nodes or blood. However, if left untreated, they can invade localised structures such as the eyelids, nerves, cartilage or bone.
Basal cell carcinomas most frequently occur on the face, ears, back of the hands, arms and shoulders. They occur equally in both men and women and most commonly affect people over the age of 40 years. BCCs are typically slow growing (months or years).
Characteristic features of BCCs may include:
- A few millimetres to several centimetres in diameter
- Waxy small raised lesions (papules) with a depressed centre
- Pearl-like and transluscent in appearance
- Ulcer-like in appearance
- Tendency to bleed
- Red and scaly, oozing or crusted areas
- Raised borders
- Black-blue or brown areas
There are several different types of BCC. These include:
Nodular Basal Cell Carcinoma
This type of BCC typically appears as a pearly translucent bump on the skin but in some cases it may be brown (pigmented). Sometimes they can bleed then heal over. Occasionally they can appear in areas of little sun exposure eg: behind the ear.
Superficial Basal Cell Carcinoma
This type of BCC appears as a pink or red patch of scaly skin and can be mistaken for patches of dermatitis or eczema. This type of BCC commonly occurs on the shoulders, back, chest and midriff, and there can be several present at one time. They can bleed if rubbed eg: with a towel. Superficial BCCs do not often grow deeply into the skin layers. However, the longer they are left untreated, the larger and deeper they can grow.
Morphoeic Basal Cell Carcinoma
This type of BCC is often difficult to diagnose and can be difficult to treat. It appears as a skin-coloured lumpy area of skin that may resemble a thickened scar. It can penetrate the deep layers of skin if left untreated.
Pigmented Basal Cell Carcinoma
This is an uncommon form of nodular BCC, which appears as a brown, blue or greyish lesion and may resemble melanoma.
Basisquamous Basal Cell Carcinoma
This is a BCC mixed with another form of skin cancer calle squamous cell carcinoma. It can be more aggressive than other types of BCC.
If a change or abnormality (lesion) develops on the skin it is important to consult a doctor as soon as possible in order for a diagnosis to be made. The doctor will look closely at the lesion, assessing its size, location and characteristics and will ask about the history of the lesion eg: how long it has been there, whether it bleeds or itches etc.
If the doctor suspects that the abnormal lesion may be cancerous, they may take a small sample of the tissue (a biopsy). The sample of tissue is sent to a laboratory where examination under a microscope can reveal whether the tissue cells are cancerous. If they are then the doctor will recommend appropriate treatment.
The treatment of a BCC will depend on its type, size and location. Early treatment enables the BCC to be more easily treated and will lessen scarring and local complications. Treatment options include:
This is the most common treatment for BCC and involves cutting out the BCC along with a small area of surrounding tissue, and stitching up the skin. For larger, more extensive BCC's (particularly if they are in a difficult position) a referral to a plastic surgeon or other appropriate specialist may be required. After excision of the BCC a graft or skin flap may be used in order to repair the defect.
This surgical technique enables BCCs and other skin cancers to be more precisely but completely excised whilst preserving as much healthy skin tissue as possible. During surgery an initial excision is made and the tissue is carefully examined under a microscope. If necessary, further slices of tissue are removed until it is clear on microscopic examination that all the cancer has been removed. Mohs surgery is performed under local anaesthetic by a dermatologist who has special training in the technique. This technique is not appropriate for the treatment of all skin cancers. It is mainly indicated in the treatment of basal and squamous cell carcinomas that are in areas of the body where preservation of surrounding tissues avoids the need for complex reconstructions, although reconstructive surgery may be required occasionally after Mohs' surgery. The technique is not appropriate for melanoma skin cancers.
This treatment uses liquid nitrogen to freeze off the BCC. This is used in the treatment of superficial BCCs only.
Curettage or shaving
This treatment uses specialised cutting instruments to remove the BCC layer by layer.
X-ray treatment to destroy the BCC may be used for lesions on the face or for lesions that are considered to be inoperable. This form of treatment is not usually recommended for people under the age of 65 years.
A special cream is applied to the BCC and the lesion is exposed to a special light (either laser or non-laser) several hours later. The photochemical reaction between the cream and the light selectively destroys the cancer cells.
A topical cream that stimulates the immune system is sometimes used in the treatment of superficial BCCs. It works by stimulating the immune system to release chemicals that help to destroy the cancer cells. The most commonly used topical medications are imiquimod cream (Aldara) and fluorouracil cream (Efudix). They are mainly effective against small superficial BCCs.
Avoiding exposure to the sun is the best way to reduce the risk of developing a BCC. If exposure to the sun is unavoidable the Cancer Society of New Zealand recommends the following precautions:
- Use a sunscreen that has sun protection factor of greater than SPF30.
- Wear a wide brimmed hat and protective clothing.
- Avoid being out in the sun between 11am and 4pm.
It is also recommended that we check our skin every 3-6 months for changes in moles or freckles. Early detection is very important and if any changes are noticed, consult a doctor.
Bader, R.S. (2013) Basal cell carcinoma. Medscape Reference: Drugs, Diseases & Procedures. New York: WebMC LLC.
Davidson, A.M., Cumming, A.D., Swainson, C.P. & Turner, N. (1999) Basal cell carcinoma. In C.Haslett, E.R. Chilvers, J.A.A. Hunter & N.A. Boon (eds.) Davidson’s principles and practice of Medicine (18th ed.) (pp 913-914) Edinburgh: Churchill Livingstone
New Zealand Dermatological Society (2012) Basal Cell Carcinoma. In DermNet. New Zealand Dermatological Society Incorporated, Auckland. www.dermnetnz.org/lesions/basal-cell-carcinoma.html
O’Toole, M.T. (Ed.) (2013) Basal Cell Carcinoma. Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis: Elsevier Mosby.
Spickler, A. R., Odle, T. G. (2005) Basal cell carcinoma. The Gale Encyclopedia of Cancer: A Guide to Cancer and Its Treatments, Second Edition. Jacqueline L. Longe, Editor. In Health and Wellness Resource Centre: Thomson Gale. Farmington Hills, MI.
Last Reviewed - 1 July 2013