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Basal Cell Carcinoma - Patient Information

What is basal cell carcinoma?

Basal cell carcinoma is the most common skin cancer in humans. It develops in the basal cell layer and can be very destructive and disfiguring. It occurs mainly on hair-bearing and sun exposed skin areas. There are many types of basal cell carcinomas which can look very different. But they all have in common that they rarely spread to other parts of the body.

Who is at risk from basal cell carcinoma and how common is it?

Melanoma and nonmelanoma (basal and squamous cell carcinoma) skin cancer are now the most common type of cancer in the Caucasian population and the incidence of skin cancer has reached epidemic proportions. Many epidemiological studies have demonstrated that the incidence of skin cancer has been increasing rapidly over the last decades. Nonmelanoma skin cancers (NMSCs) constitute more than one-third of all cancers in the United States with an estimated incidence of over 600,000 cases per year. NMSCs are the most common malignancies occurring in the Caucasian population each year. Of these 600,000 cases approximately 500,000 are basal cell carcinomas (BCCs) and 100,000 to 150,000 are squamous cell carcinomas (SCCs). The standardized ratio of BCC to SCC is roughly 4 to 1. The incidence of NMSC (BCC and SCC) is 18 times greater than that of malignant melanoma. However, incidence data of high epidemiological quality on NMSC are sparse because traditional cancer registries often exclude NMSC or are at least incomplete. Miller & Weinstock (1994) estimated the 1994 NMSC incidence in the United States to be between 900,000 and 1,200,000. The lifetime risks were estimated to be 28% to 33% for BCC and 7% to 11% for SCC (lifetime risk of developing NMSC for a child born in 1994)

BCC represents 75% of NMSC and is, therefore, the most common malignant disease throughout the world. Silverberg et al (1990) estimated the average annual incidence of BCC in the United States to 191 new lesions per 100,000 white persons According to the estimates (lowest and highest estimated incidence rates) of Miller & Weinstock (1994) the age-adjusted incidence rates per 100,000 whites per year (1994) in the United States were as follows: BCC (men) 407–485, BCC (women) 212–253), SCC (men) 81-136, SCC (women) 26-59). For South Wales (United Kingdom) the age-standardized (world standard population) incidence rates per 100,000 population in 1998 were lower: BCC (men) 127.9, BCC (women) 104.8, SCC (men) 25.2, SCC (women) 8.6 (Holme et al. 2000). Although these incidence rates are high, they do not approach the rates described from Australia. The incidence is 1% to 2% per year (1000 to 2000 per 100,000 per year): Townsville, Australia (Buettner et al. 1998): BCC (male) 2058, BCC (female) 1195, SCC (male) 1332, SCC (female) 755); Nambour, Australia Green et al. 1996): BCC (male) 2074, BCC (female) 1579, SCC (male) 1035, SCC (female) 472.

There is an increased risk of NMSC in whites, especially those who have blue eyes, a fair complexion, sunburn easily, suntan poorly, freckle with sun exposure, have red, blond, or light-brown hair (Celtic ancestry). NMSC is uncommon in blacks, Asians, and Hispanics. There is a higher incidence of BCC in Albino blacks than in normally pigmented blacks. Compared with whites, blacks have a decreased risk of BCC on sun-exposed areas, but the same incidence of BCC on covered skin. In contrast to whites, sunlight does not appear to be an important etiologic factor for SCC in blacks because lesions occur on non-sun-exposed regions of the body. SCC in blacks arise most often on sites of preexisting inflammatory skin conditions, burn injuries, or trauma. SCC in blacks are often seen in scars, burns, or ulcers.

The incidence of NMSC is increasing rapidly. In white populations in Europe, the United States, Canada, and Australia the average increase of NMSC was 3-8%. Chronic sun exposure is the main cause of NMSC. Over 80% of NMSCs occur on areas of the body that are frequently exposed to sunlight, such as head, neck, and back of the hands. BCC is also most commonly found on the nose. The rising incidence rates of NMSC is probably due to a combination of increased sun exposure or exposure to ultraviolet light, increased outdoor activities, changes in clothing style, increased longevity, and ozone depletion. In incidence of NMSC in Caucasians increases proportionally with proximity to the equator, with the incidence of SCC doubling for each 8-10 degree decline in latitude. UV dosage per unit time at the equator in the Pacific is very high, about 200% that of Europe or the northern US, and 30% higher than that of the southern US. The incidence of NMSC is elevated in individuals with a high cumulative exposure to UV light, such as outdoor workers, or those with more frequent outdoor activities. The incidence is also increasing with age: According to Holme et al. (2000) in 1998 the incidence of BCC in individuals over 75 years old was approximately 5 times higher compared to individuals between 50 and 55 years old, and for SCC approximately 35 times higher. The incidence of SCC increases more rapidly with age than does BCC. The reported increases in the incidence of melanoma and NMSC have partially been attributed to a larger amount of UVB radiation reaching the surface of the earth as a result of ozone depletion in the atmosphere. The ozone layer has decreased by approximately 2% over the past 20 years. A 2% decrease in ozone concentration will increase biologically effective radiation from the sun by approximately 4%. It was estimated that this additional UV radiation will cause a 6-12% increase in NMSC in exposed populations.

Once an individual develops a NMSC, there is a 36%-52% chance that a new skin cancer will appear within 5 years.

What causes basal cell carcinoma and how does it develop?

There are several factors known to cause basal cell carcinoma. Probably the most important factor is the genetically defined individual skin type. People with fair or sun-sensitive skin, with red hair and many freckles are at risk of developing basal cell carcinoma. Next to the genetic factor the accumulated exposure to the sun´s UV-radiation during one's lifetime has been proven to be responsible for this type of skin cancer since the majority of basal cell carcinomas appear on sun exposed areas such as the face, scalp, ears, and upper parts of chest and back.

Basal cell carcinoma can also emerge from continuous exposure to chemical cancer-causing substances (chemical carcinogens) such as tars, oils, and arsenic. Also X-rays and/or radiotherapy may act as a cofactor for developing basal cell carcinoma. A further component that may increase the risk of the occurrence of this particular skin cancer is the presence of chronically injured skin. Although basal cell carcinoma may appear on apparently healthy skin it usually is related to damaged or injured skin. Scars from burning or skin areas which are constantly inflamed or irritated by constant physical stimulation such as hair extraction or friction or pressure can be risk afflicted conditions.

Also patients who have to undergo immunosuppressive treatment due to an organ transplantation, people with an inherent immune defect or AIDS-patients carry an increased potential of developing basal cell carcinoma.

There are also some rare genetically determined disorders which may increase the risk of developing basal cell carcinoma.p>

How to spot basal cell carcinoma

Since different forms of basal cell carcinoma exist, which can differ very much in their appearance, an experienced dermatologist should be consulted. If the lesion is scaly or crusty, the dermatologist will have to remove the top layer of the area to get to the tissue underneath which may reveal certain diagnostic characteristics of basal cell carcinoma. If there is any doubt and the lesion cannot clearly be differentiated from other skin disorders, a piece of the lesion has to be removed for further examination (biopsy).

What does it look like?

Basal cell carcinoma can have many different appearances. What all the different types have in common is the area where they usually appear. The preferred site for basal cell carcinoma is the face but it can also occur on the scalp, the ears, and the upper part of the chest and back. They can start out as a small translucent nodule with little blood vessels shining through, as a red flat but slightly raised area or as a scaly red to white-brownish patch. Sometimes basal cell carcinoma may be of brown to black color looking similar to a mole. Basal cell carcinoma may itch, be sensitive to touch or even bleed.

Usually basal cell carcinoma progresses slowly but gradually. If it is left untreated it may grow very destructive entering deeper tissue and causing major disfigurement.

How to prevent basal cell carcinoma

The best way to prevent basal cell carcinoma is avoiding any implicated risk factors. Therefore protect yourself from UV radiation and avoid contact to cancer causing substances (carcinogens).

Is it really basal cell carcinoma?

There are many skin diseases that may look similar to BCC. Just because you have a rough spot on your skin does not mean you have cancer, yet it is something that should be taken seriously. If you have noticed a strange looking area of skin please see your dermatologist or doctor.

What could go wrong?

Basal cell carcinoma may invade surrounding tissue, and if left untreated may ulcerate and cause major disfigurement. Sometimes the invasion may reach bone and nerve tissue. Ulcerated carcinomas are prone to become infected. Basal cell carcinoma has a very low tendency (below 0.1 %) to spread to other parts of the body (metastize).

I have basal cell carcinoma what can I do?

There are several effective treatment options available for squamous cell carcinoma. To decide which one will be the most appropriate highly depends on the individual case and should be discussed with your physician.

Moh´s Surgery / Surgery

Surgery is the most effective treatment. The tumor will be excised and the wound will be closed with a few stitches (amount depending on size of affected area). Surgery always requires a local anaesthetic. Usually the wound will heal within two weeks. Moh´s surgery is a special type of surgery where the surgeon is specially trained. During the surgery a microscopic method is used to make sure all of the affected skin areas are excised.

Advantages of the treatment

It has the highest cure rate of all surgical treatments.
The removed tissue can be examined microscopically to determine if the tumor has been totally excised.