BCCs are abnormal, uncontrolled growths or lesions that arise in the skin’s basal cells, which line the deepest layer of the epidermis (the outermost layer of the skin). BCCs often look like open sores, red patches, pink growths, shiny bumps, or scars and are usually caused by a combination of cumulative and intense, occasional sun exposure.
BCC almost never spreads (metastasizes) beyond the original tumor site. Only in exceedingly rare cases can it spread to other parts of the body and become life-threatening. It shouldn’t be taken lightly, though: it can be disfiguring if not treated promptly.
More than 4 million cases of basal cell carcinoma are diagnosed in the U.S. each year. In fact, BCC is the most frequently occurring form of all cancers. More than one out of every three new cancers is a skin cancer, and the vast majority are BCCs.
After the physician’s examination, the diagnosis of BCC is confirmed with a biopsy. In this procedure, the skin is first numbed with local anesthesia. A sample of the tissue is then removed and sent to be examined under a microscope in the laboratory to seek a definitive diagnosis. If tumor cells are present, treatment is required. Fortunately, there are several effective methods for eliminating BCC. Choice of treatment is based on the type, size, location, and depth of penetration of the tumor, the patient’s age and general health, and the likely outcome to his or her appearance.
Treatment can almost always be performed on an outpatient basis in the physician’s office or at a clinic. With the various surgical techniques, a local anesthetic is commonly used. Pain or discomfort during the procedure is minimal, and pain afterwards is rare.
Electrodessication and Curretage
This technique is usually reserved for small lesions. The growth is scraped off with a curette, an instrument with a sharp, ring-shaped tip), then the tumor site is desiccated (burned) with an electrocautery needle. The procedure has cure rates generally above 95 percent. In some areas of the body, it is repeated a few times to help assure that all cancer cells are eliminated. Local anesthesia is required. The technique may not be as useful for aggressive BCCs, those in high-risk sites, or sites that would be left with cosmetically undesirable results. Typically, a round, whitish scar is left at the surgery site.
A physician trained in Mohs micrographic surgery removes a thin layer of tissue containing the tumor. While the patient waits, frozen sections of this excised layer are mapped in detail and examined under a microscope, generally in an on-site laboratory. If cancer is present in any area of the excised tissue, the procedure is repeated only on the body area where those cancer cells were identified (the tissue mapping allows the Mohs surgeon to pinpoint this area of the body), until the last excised layer viewed microscopically is cancer-free. This technique can save the greatest amount of healthy tissue and has the highest cure rate, 99 percent or better. It is often used for large tumors in cosmetically important areas, and those that have recurred, are poorly demarcated (hard to pinpoint), or are in critical areas around the eyes, nose, lips, and ears, temple, scalp, or fingers.
Using a scalpel, the physician removes the entire growth along with a surrounding border of apparently normal skin as a safety margin. The skin around the surgical site is closed with stitches, and the tissue specimen is sent to the laboratory to verify that all cancerous cells have been removed. Cure rates are generally above 95 percent in most body areas, similar to those of curettage and electrodesiccation. A repeat excision may be necessary on a subsequent occasion if evidence of skin cancer is found in the specimen.
X-ray beams are directed through the skin at the tumor, with no need for cutting or anesthesia. Total destruction usually requires several treatments over a few weeks, or sometimes daily for one month. This is ideal for tumors hard to manage surgically and for elderly patients or others in poor health. Cure rates are around 90 percent. Although radiation limits damage to adjacent tissue, it can involve long-term cosmetic problems and radiation risks.
Tumor tissue is destroyed by freezing. Liquid nitrogen is applied to the growth with a cotton-tipped applicator or spray device, freezing it without requiring any cutting or anesthesia (though a local anesthetic can be used, since the technique often involves a modest amount of pain). The procedure may be repeated at the same session to ensure total destruction of malignant cells. The growth subsequently blisters or becomes crusted and falls off, usually within weeks. Temporary redness and swelling can occur, and in most cases, pigment may be lost at the site. Cryosurgery is effective for the most common tumors, especially superficial BCC, and is useful for patients with bleeding disorders or intolerance to anesthesia. This method is used less commonly today, and has a lower cure rate than the surgical techniques–approximately 85-90 percent, depending on the physician’s expertise.
Photodynamic Therapy (PDT)
PDT is FDA-approved for the treatment of superficial or nodular BCC, with cure rates ranging from 70 to 90 percent. A light-sensitizing agent, topical 5-aminolevulinic acid (5-ALA), is applied to the lesion in the physician’s office. Subsequently, the medicated area is activated by a strong blue light; theoretically, this will selectively destroys BCCs while causing minimal damage to surrounding normal tissue. Some redness, pain, and swelling can result. Patients must strictly avoid sunlight for at least 48 hours, or UV exposure may further activate the medication, causing severe sunburn.
Some lasers vaporize (ablate) the skin’s top layer to destroy lesions. Others (non-ablative lasers) penetrate the skin without removing the top layer; one such laser has been shown in some cases to treat small, superficial BCCs successfully. Laser therapy is not yet FDA-approved for BCC, but is sometimes used as a secondary therapy when other techniques are unsuccessful. Laser treatment has recurrence rates similar to those of PDT.
These creams, gels, or solutions are used to treat limited, specific BCCs.
Imiquimod is FDA-approved only for superficial BCCs, with cure rates generally between 80 and 90 percent. The cream is rubbed gently into the tumor five times a week for up to six weeks or longer. The first in a new class of drugs that work by stimulating the immune system, it causes the body to produce interferon, a chemical that attacks cancer.
5-Fluorouracil (5-FU), a chemotherapy drug approved to treat internal cancers, also has been FDA-approved for superficial BCCs, with similar cure rates to imiquimod. The liquid or cream is gently rubbed into the tumor twice a day for three to six weeks. Side effects are variable, and some patients do not experience any discomfort, but redness, irritation, and inflammation usually occur.
It is important to note that (unlike Mohs surgery and excisional surgery), curettage and electrodesiccation, radiation, cryosurgery, and topical medications all have one significant drawback in common – since no tissue is examined under the microscope, there is no way to determine how completely the tumor was removed.
vismodegib (Erivedge™), an oral medicine, was approved by the FDA in 2012 for extraordinarily rare cases of metastatic BCC or locally advanced BCC that become dangerous and even life-threatening. The first medicine ever for advanced BCC, it works by blocking the “hedgehog” signaling pathway, which is a key step in the development of BCC. Vismodegib is approved only for very limited circumstances where the nature of the cancer precludes other treatment options (such as surgery or radiation). Due to a risk of birth defects, vismodegib should not be used by women who are pregnant or may become pregnant. Birth control must be used by couples if the woman is capable of becoming pregnant.
sonidegib (Odomzo®), a second oral hedgehog inhibitor drug, was approved by the FDA in 2015 for patients with locally advanced BCCs, specifically patients whose tumors have recurred following surgery or radiation therapy, or who are not candidates for surgery or radiation therapy. Like vismodegib, sonidegib can cause death or severe birth defects in a developing fetus when administered to a pregnant woman; both male and female patients need to be warned of these risks and advised to use effective contraception. Other potential side effects include serious musculoskeletal problems, increased serum creatine kinase levels, muscle pain, and spasms.
Several other targeted hedgehog inhibitors are also being investigated as potential treatments for locally advanced and metastatic BCC.