Skin cancers can arise from a number of different components of the skin. Often a differentiation is made between melanoma and nonmelanoma skin cancers because the prognosis for melanoma is much worse than for the other skin cancer types. Basal cell skin cancer has the highest prevalence of all skin cancers, but is often easily cured. Squamous cell skin cancer also occurs in many people, and it has a slightly increased risk of complications as compared with basal cell cancers.
Many people make the distinction between melanoma and nonmelanoma skin cancer because the two groups have very different fatality rates. Melanoma is an unregulated, abnormal growth of the skin cells responsible for the pigmentation of the skin. It tends to spread to other areas of the body more readily than other types of skin cancer, and therefore causes a more extensive disease. Although the cure rate for melanoma is approximately 85%, in patients who have disease that has spread to distant organs at the time of diagnosis, 90% pass away within five years. The other types of skin cancer rarely result in death.
Nonmelanoma skin cancer falls into two basic categories, basal cell carcinoma and squamous cell carcinoma. Basal cell carcinoma is a cancer that arises from cells normally present in the bottom part of the epidermal layer of the skin. The cancer presents as a skin lesion, and classically is a hard, raised growth that has a pearly appearance. Often telangiectasias, or red-colored dilated capillaries, can be seen within the lesion. The most common location for these skin cancers is on sun-exposed regions of the skin, such as on the face.
The mainstay of treatment of basal cell skin cancer is surgical removal. These cancers typically grow by invading local structures, and do not typically spread to distant areas of the body via the blood or lymphatic system. Most patients do not require treatment with chemotherapy, radiation therapy, or invasive surgeries.
Squamous cell carcinoma is the other major type of nonmelanoma skin cancer. It is abnormal growth of the cells located on the outer surface of the skin. Risk factors for developing this cancer include prolonged exposure to sunlight, severe skin burns, treatment with medications that lower the immune system, and exposure to arsenic. This type of cancer presents as a skin lesion that can be scaly or ulcerated, and is often seen on sun-exposed surfaces.
Like basal cell skin cancer, squamous cell skin cancer is treated with surgical removal. Although this type of nonmelanoma skin cancer has a greater risk of metastasis than basal cell skin cancer, the risk of this happening is still less than 1 percent. Patients with disease that has spread to distant parts of the body might require systemic chemotherapy.
