Understanding Skin Cancer

FAST FACTS

  • Skin Cancer is the most common cancer in the United States and worldwide.
  • More people are diagnosed with skin cancer each year in the United States than all other cancer combined.
  • By the age of 70 one in five Americans will develop skin cancer.
  • Basal and squamous cell skin cancers are the most common types of skin cancer.
  • About 90% of skin cancers (nonmelanoma) are directly related to exposure to ultraviolet radiation (UV) from the sun.
  • In the past ten years the incidence of melanoma has increased 47%.
  • The majority of melanomas are caused by ultraviolet radiation from the sun.

Where do skin cancers start?

Most skin cancers start in the top layer of skin (the epidermis) and are often related to sun exposure, Cancer starts when cells in the body begin to grow out of control. The three types of cells in the top layer of the skin are:

Squamous cells

Flat cells in the upper (outer) part of the epidermis, which are constantly shed as new ones form. When these cells grow out of control, they can develop into squamous cell skin cancer (also called squamous cell carcinoma).

Basal cells

Cells are in the lower part of the epidermis, called the basal cell layer. These cells constantly divide to form new cells to replace the squamous cells that wear off the skin’s surface. As these cells move up in the epidermis, they get flatter, eventually becoming squamous cells. Skin cancers that start in the basal cell layer are called basal cell skin cancers or basal cell carcinomas.

Melanocytes

These cells make the brown pigment called melanin, which gives the skin its tan or brown color. Melanin acts as the body’s natural sunscreen, protecting the deeper layers of the skin from some of the harmful effects of the sun. Melanoma skin cancer starts in these cells.

Basal cell carcinoma

Basal cell carcinoma (also called basal cell skin cancer) is most common type of skin cancer. More than 4 million cases are diagnosed in the United States each year.

These cancers usually develop on areas exposed to the sun, especially the face, head, and neck. They are slow growing cancers. It’s very rare for a basal cell cancer to spread to other parts of the body. But if it's left untreated, basal cell cancer can grow into nearby areas and invade the bone or other tissues beneath the skin.

If not removed completely, basal cell carcinoma can come back (recur) in the same place on the skin. People who have had basal cell skin cancers have an increased risk of developing new ones in other places.

When detected early, most basal cell carcinomas can be treated and cured. If you’ve been diagnosed with a small or early basal cell carcinoma, there a number of effective treatment available. A dermatologist will recommend the appropriate treatment option, be sure and ask about all of your treatment options including radiation therapy.

Squamous cell carcinoma

About 2 out of 10 skin cancers are squamous cell carcinomas (also called squamous cell cancers).

These cancers commonly appear on areas exposed to the sun, such as the face, ears, neck, lips, and backs of the hands. They can also develop in scars or chronic skin sores elsewhere. They sometimes start in actinic keratoses, a pre-cancerous skin condition.

Squamous cell cancers can usually be removed completely (or treated in other ways), although they are more likely than basal cell cancers to grow into deeper layers of skin and spread to other parts of the body.

Most squamous cell carcinomas of the skin can be cured when found and treated early. More advanced squamous cell carcinomas of the skin are more difficult to treat and can become dangerous, spreading to local lymph nodes, distant tissues and organs. If you have been diagnosed with a squamous cell carcinoma that has not spread, there are several treatment options available. A dermatologist will recommend the appropriate treatment option, be sure and ask about all of your treatment options including radiation therapy.

Melanoma

Melanoma is the most serious form of skin cancer. These cancers develop from melanocytes, the pigment-making cells found in the epidermis. Although melanomas are much less common than basal and squamous cell cancers, they are more likely to grow and spread if left untreated.

The vast majority of melanomas are caused by the sun, other possible causes include genetics and immune system deficiencies. On average a person’s risk of developing melanoma doubles if they have had more than five sunburns. But just one blistering sunburn in childhood or adolescence more than doubles the risk of developing melanoma later in life. The overall incidence of melanoma continues to rise in the United States.