Skin cancer is the most common type of cancer in New Mexico and the United States. In fact, skin cancer is more common than all other types of cancer combined. The primary cause of all forms of skin cancer is ultraviolet light which damages the DNA in skin cells causing them to grow abnormally. The three most common types of skin cancer, comprising 99% of all skin cancers, are basal cell carcinoma, squamous cell carcinoma, and melanoma. They all begin from different cell types and one form does not develop into another form. The two most common kinds of skin cancer- basal cell carcinoma and squamous cell carcinoma- are highly curable. Melanoma is less common and potentially more dangerous than the other kinds of skin cancer.
Basal cell carcinoma is the most common and least aggressive type of skin cancer, accounting for 80% of all diagnosed skin cancers. In fact, one out of five individuals will develop a basal cell carcinoma. This skin cancer begins in the basal cells in the lower part of the epidermis, usually grows very slowly, and does not tend to spread to other areas of the body. Left untreated, basal cell carcinoma can damage surrounding nerves, muscle, and bone.
Squamous cell carcinoma is potentially more aggressive than basal cell carcinoma. The second most common form of skin cancer, it begins just beneath the surface of skin in the squamous layer. It most often develops in sun-exposed sites, but can also develop in mucous membranes and genitals. Unlike basal cell carcinoma, squamous cell carcinoma is more likely to spread through the body (16% chance of metastasis).
Melanoma is the least common and potentially more dangerous than the other common forms of skin cancer. It accounts for 3% of all skin cancer cases and is responsible for 75% of skin cancer deaths. It originates in melanocytes, the pigment-producing cells of the skin. If detected early, melanoma cure rates are high. Once melanoma spreads through the body, cure rates are much lower.
Treatment of Skin Cancer
The treatment method chosen depends upon the type of skin cancer, location, size and any previous treatments. In addition, the treatment of each skin cancer must be individualized, taking into consideration such factors as the patient’s age and other health problems. In some instances, more than one type of skin cancer therapy may be appropriate. Dr. Reisinger will discuss treatment alternatives with you to help decide what is the best treatment in your individual case.
Treatments of basal cell carcinoma and squamous cell carcinoma include curettage and electrodesiccation (scraping and destroying the tissue by electric current), surgical excision, chemotherapy creams or immune-modulating creams, and radiation therapy. In these therapies, the physician must make an educated visual estimate about the size of the cancer and the margins outside the cancer that must be removed for safety.
Treatments relying on the human eye to determine the extent of the cancer may prove ineffective. Removal of skin cancer is often complex because all skin cancers begin beneath the surface of skin and their margins are difficult to predict. Often times, cancer visible to the naked eye is just the ‘tip of the iceberg’ with roots extending beyond the boundaries of the visible center. If these cancer cells are not completely removed, they can lead to a recurrence of the cancer. When too much tissue is removed, healthy tissue is lost, resulting in larger wounds and larger scars. Mohs surgery is the most effective treatment for basal cell carcinoma and squamous cell carcinoma. Because the Mohs procedure is microscopically controlled, it removes all the cancer and preserves as much healthy tissue as possible. This cost effective method produces the smallest wound, the smallest scar, yet the highest cure rate of any other modality.
While Mohs surgery is the most effective treatment for basal cell carcinoma and squamous cell carcinoma, melanoma is best treated with a wide surgical excision. The recommended excision margin depends on the thickness of the melanoma reported in the initial biopsy specimen. A sentinel node removed at the time of definitive re-excision may be indicated for staging purposes. While some centers will remove melanoma with Mohs micrographic surgery, many do not because it is more difficult to see the melanoma cells on the Mohs frozen section than the standard permanent tissue section. In select cases of melanoma in situ on the face, a combined approach of tissue mapping with ‘en face’ permanent section processing, termed ‘Slow Mohs’, may be appropriate for tissue conservation.