Basal cell carcinoma is a type of skin cancer. It is a malignant epithelial cell tumor that begins as a papule (a small, circumscribed, solid elevation of the skin) and enlarges peripherally, developing into a crater that erodes, crusts and bleeds. Metastasis is rare, but local invasion destroys underlying and adjacent tissue. In 90 percent of all cases, the lesion is seen between the hairline and the upper lip.
Basal cell carcinoma (BCC) is the most common and least lethal form of all cancers. In the United States, basal cell cancer accounts for 90 percent of all skin cancers in the southern states, and 47 percent in the northern states.
It occurs most frequently in people over 45 years of age, and almost twice as often in men as in women. The incidence is far more prevalent among Caucasians. It occurs less often in Asians and rarely among African-Americans. The risk of skin cancer is related to the amount of sun exposure and pigmentation in the skin. The longer the exposure to the sun and the lighter the skin, the greater the risk of skin cancer.
The most common type of basal cell carcinoma is nodular basal cell carcinoma, a flesh-colored (cream to pink), round or oval translucent nodule with overlying small blood vessels and a pearly-appearing rolled border.
The second type of BCC is the pigmented lesion. This is darker than the nodular type, appearing blue, brown or black. It may be similar in appearance to the very aggressive malignant melanoma tumor. It is very important to distinguish between malignant melanomas and pigmented BCC.
A third type of BCC is the superficial type, which appears as red, and often scaly, localized plaque. It is frequently confused with psoriasis or eczema.
The main cause of basal cell carcinoma of the skin is ultraviolet radiation from the sun. The earth's ozone layer offers protection from UV radiation by blocking it. However, depletion of the ozone layer since the late 1970s has increased the damage to the skin that can result in cancer. Clinical trials are determining if this skin cancer can be prevented.
The five most typical characteristics of basal cell carcinoma are quite different from each other. Frequently, two or more features are present in one tumor. In addition, basal cell carcinoma sometimes resembles non-cancerous skin conditions, such as psoriasis or eczema. Only a trained physician, usually a dermatologist, can diagnose this cancer.
It is advisable to learn the signs of basal cell carcinoma and examine the body regularly, as often as once a month, if at high risk. A full-length mirror and a hand-held mirror can be very useful for the less visible parts of the body. The five warning signs of basal cell carcinoma are:
- An open sore that bleeds, oozes or crusts, and remains open for three or more weeks. A persistent, non-healing sore is a very common early manifestation.
- A reddish patch or an irritated area, frequently occurring on the chest, shoulders, arms or legs. Sometimes the patch crusts. It may also itch or hurt. At other times, it persists with no noticeable discomfort.
- A smooth growth with an elevated, rolled border and an indentation in the center. As the growth slowly enlarges, tiny blood vessels may develop on the surface.
- A shiny bump (or nodule) that is pearly or translucent and is often pink, red or white. The bump can also be tan, black or brown, especially in dark-haired people, and can be confused with a mole.
- A scar-like area (white, yellow, or waxy in appearance) which often has poorly defined borders. The skin itself appears shiny or taut. Although a less frequent sign, it can indicate the presence of an aggressive tumor.
Diagnosis requires the removal of some tissue for a biopsy (a microscopic examination for cancer cells). If it is a small cancer, the biopsy also frequently removes the cancer. However, if the area is sizable, more tissue may have to be removed until there are "clean margins."
Treatment depends on the size of the tumor and the general health of the patient. Surgery is usually the treatment used to remove the cancer. There are a number of ways the surgery can be performed:
- Electrodessication and Curettage - the cancer is burned and removed with a sharp instrument.
- Cryosurgery - the cancer is killed by freezing it.
- Excision - the cancer is cut from the skin along with some healthy tissue around it.
- Micrographic surgery - the cancer is cut from the skin, along with some of the healthy surrounding tissue. The doctor then uses a microscope to examine the area for any remaining cancer cells.
- Laser surgery - a narrow beam of light is used to remove the cancer.
Other treatments include radiation therapy, the application of topical chemotherapy to the cancer site and Mohs' micrographic surgery. The aim of any treatment is the removal of the cancer with the least disfigurement.
Although a basal cell carcinoma has been removed, another growth can develop in the same place or nearby area. These recurrences typically take place within the first two years following surgery. Basal cell carcinomas on the scalp, nose and corners of the nose, are especially troublesome. Therefore, it is important to examine the site previously treated.