Basal cell carcinoma (BCC) is not only the most common of all skin cancers, but it is also the most common all cancers of any type. About 8 out of 10 skin cancers are basal cell carcinomas. In the United States alone, over 4 million cases will be diagnosed each year.
Risk factors for basal cell carcinoma
Exposure to ultraviolet radiation from sunlight and tanning beds is the most significant risk factor for BCC. However, other environmental and genetic factors also contribute to the development of basal cell carcinoma.
The risk of the sun’s ultraviolet rays is directly tied to the person’s sun exposure habits. It is also related to their personal susceptibility to the harmful radiation.
Studies show that intense, intermittent sun exposure increases the risk of BCC compared to a similar radiation exposure that is delivered continuously over the same period of time.
Individuals with fair skin, light-colored eyes, freckling, red hair, and a history of past sunburns all increase the chances of BCC development.
Other risk factors include the following:
- arsenic exposure from contaminated well water or seafood
- a history of radiation therapy commonly used for treating conditions like psoriasis or facial acne
- long term immunosuppressive therapy commonly prescribed for organ transplant patients
Inherited disorders that may increase the risk of developing BCC include:
- Nevoid basal cell carcinoma syndrome
- Xeroderma pigmentosa
- Bazex syndrome (Bazex-Dupre-Christol syndrome)
- Oculocutaneous albinism
The number of BCCs has been increasing
The number of BCCs has been increasing for many years likely as a result of better skin cancer detection, people getting more sun exposure, and increasing longevity.
Despite its high incidence, BCCs rarely metastasize or spread to another part of the body. There are fewer than 4,000 deaths annually from basal cell carcinoma and those that occur are almost always associated with a rare more aggressive form, late diagnosis or neglect of treatment.
Although BCC has a high cure rate, the diagnosis should not be taken lightly as certain forms may be very aggressive and cause the destruction of surrounding tissue, disfigurement or nerve or muscle injury. When found early, however, basal cell carcinomas are easily treated.
How BCC begins
Basal cell carcinoma begins in a basal cell, which is a cell in the lowest layer of the most superficial layer of skin (the epidermis). These basal cells are the cells that give rise to the new skin cells as the old ones die off.
Most basal cell carcinomas develop on sun-exposed surfaces, especially on the head and neck. Fortunately, most tend to grow slowly.
What does a BCC look like?
BCCs may appear as a white or pearly bump (light brown to black in darker complexion individuals), a flat, scaly, red or pink patch, or a white waxy scar that doesn’t go away. Sometimes they resemble other skin conditions like psoriasis or eczema. Hence, if you observe any worrisome change in your skin, consult your dermatologist.
After the diagnosis of BCC is confirmed, the choice of treatment is based on the type, size, location, and depth of the tumor. The physician will also consider the patient’s age, overall general health, and the outcome to his or her appearance.
Treatment of BCC is most often performed on an outpatient basis (i.e. in a doctor’s office or surgical center). The majority of BCCs are removed with a local anesthetic, with minimal discomfort both during and after the procedure.
Surgical treatment options include:
Curettage and Electrodesiccation
This is a common treatment for small BCCs. Using a curette, a hand-held instrument with a sharp ring-shaped tip, the tumor is scraped off. Heat is then applied to the treated area with an electrocautery needle. This procedure is often repeated to assure complete removal of the tumor. Cure rates are better than 95% with this technique.
The tumor and a small border of normal skin are removed with a scalpel. The removed tissue is sent to the laboratory for pathology and to assure all the tumor is removed. The resulting wound is closed with sutures. Cure rates, similar to curettage and electrodesiccation, are around 95%.
Mohs Micrographic Surgery
A specially trained doctor performs a staged removal of the tumor. While the patient waits, sections of the tumor are removed and evaluated to assure complete tumor removal. Although Mohs surgery is the most tedious type of skin cancer removal for the patient, it is also the most effective, with cure rates approaching 99% or better. Mohs surgery is often used for larger tumors, aggressive tumors, recurrent cancers, and tumors that are located in critical areas on the face, like around the eyes, lips, and ears, or on the scalp and fingers.
Non-surgical treatment options include:
The tumor is exposed to X-beam radiation. After several treatments spanning several weeks, the tumor is destroyed. Although the cure rates are only about 90%, this treatment option is ideal for elderly patients when surgical procedures are not an option or when the tumor occurs in areas that are difficult to manage surgically.
Despite what the name implies, this is not a traditional surgery. Rather, the skin cancer is destroyed by applying liquid nitrogen with a cotton applicator or spray device. The procedure may be repeated several times to ensure adequate destruction of the cancer. This freezing technique leaves a blister or wound that falls off over the next several days to weeks. A loss of pigment at the treatment site may occur after this procedure. Cure rates for this type of removal are only 85-90%.
Topical 5-aminolevulinic acid (5-ALA), a light-sensitizing agent, is applied to the skin cancer in the physician’s office. The pre-treated area is then exposed and activated by a blue light that selectively destroys the cancerous tumor. Local reactions at the treated sites may occur. Patients must avoid sun exposure for several days after treatment. Cure rates range from 70 – 90%.
Both imiquimod and 5-Fluorouracil are FDA approved for the treatment of superficial BCCS. Cure rates are between 80 – 90% for both creams.
Vismodegib, a targeted therapy approved by the FDA in 2012 is reserved for very rare metastatic BCC or advanced life-threatening cases of BCC. In 2015, the FDA approved a second oral medication, sonidegib, indicated for patients with advanced BCCs, recurrent tumors, or for those where surgery or radiation therapy is not an option. Both of these drugs may increase the risk of birth defects and therefore, should not be used by women who are pregnant or plan to become pregnant.
The bottom line
Basal cell carcinoma is the most common of all skin cancers, however, early diagnosis and treatment is almost always associated with a good prognosis.
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Originally published on December 17, 2018, it was reviewed and updated by the author for republication on March 7, 2020.