Skin Cancer

Skin cancer, which is the most common form of cancer in the United States, is the result of the abnormal growth of skin cells. Cancer can affect skin anywhere on the body, but most frequently appears on skin that is exposed to the sun. There are more than a million new cases of skin cancer in the United States each year. Although most cases of skin cancer can be successfully treated, it is still important to keep skin safe and healthy and try to prevent this disease.

Types of Skin Cancer

There are three major types of skin cancer, and they affect different layers of the skin. These types derive their names from the variety of skin cell affected in each case.

Basal Cell Carcinoma

Basal cell skin cancer occurs in the basal cell layer of the skin, the layer under the squamous cells, and is the most common type of skin cancer in people with fair skin. It commonly occurs on areas of the skin that have been exposed to the sun, such as the face. It rarely spreads to other parts of the body, but in rare cases may invade adjacent tissue. It may also recur in the same location after excision.

Squamous Cell Carcinoma

Squamous cell carcinoma occurs in the squamous cells, and is the most common type of skin cancer in people with dark skin, who typically get it in places, such as the legs or feet, that have not been exposed to the sun. In people with fair skin, it usually occurs in sun-exposed areas such as on the face, head, ears and neck. Squamous cell skin cancer can metastasize to other parts of the body, so it is important to treat it in a timely manner.


melanocyte lowest layer of epidermis

Melanoma is the most aggressive type of skin cancer and the most likely to metastasize. It occurs in the melanocyte cells of the skin, the cells that provide pigment to the skin by producing melanin. Melanomas can form anywhere on the body, regardless of past exposure to sun.

A common type of precancer, known as actinic or solar keratosis, typically appears as a scaly or crusty bump on the skin's surface. This type of lesion is usually treated by freezing to prevent it from becoming malignant.

Causes of Skin Cancer

Skin cells are constantly dying and being replaced by new cells during a process controlled by DNA. When DNA is damaged, often as a result of ultravioltet radiation from sunlight or tanning parlors, the process is corrupted. Abnormal tissue growth can then occur, either because new, unneeded cells may form or because older cells may not die. This abnormal tissue growth results in the development of a tumor.

Some skin cancer affects areas of the skin that have not been exposed to the sun. Other factors that increase the risk for develepment of a skin malignancy include:

  • Fair complexion
  • Presence of moles
  • Weakened immune system
  • Heredity factors
  • Smoking

Because the body absorbs more ultraviolet radiation as we grow older, increasing age is also a risk factor for skin cancer.

Symptoms of Skin Cancer

Skin cancer is often identified as a new lesion on the skin, or a pre-existing growth that noticeably changes. Skin cancers can appear anywhere on the body, but common locations are:

  • Scalp
  • Face (lips, nose, cheek)
  • Neck or chest
  • Arms, legs or hands

Patients should be alert for the appearance of any of the following:

  • Pearly or waxy bump
  • Moles that change color or shape
  • Flesh-colored or brown scar-like lesion
  • Firm, red nodule
  • Crusted, flat lesion
  • Large brown spot with darker speckles
  • Shiny, firm bumps

Diagnosis of Skin Cancer

To diagnose skin cancer, the dermatologist checks the skin for any unusual growths or abnormal patches of skin. Any lesions the patient is concerned about should be pointed out and examined by the doctor. If the dermatologist suspects a malignancy is present, a biopsy is performed during the same visit. A biopsy involves removing a sample of targeted tissue to be examined under a microscope.

Once the results of the biopsy are reviewed, the doctor will know whether cancerous tissue is present and, if so, what type of malignancy has been diagnosed. This information is delivered to the patient and a course of treatment is mapped out. Those who experience any skin changes, or have changes to existing moles or birthmarks, should see a doctor as soon as possible; early detection is key in successfully treating skin cancer.

It is essential for patients to be vigilant in checking their own skin on a regular basis so that any changes can be noted and seen by the dermatologist as promptly as possible since early detection is invaluable in successfully treating skin cancer. Regular full body screening is recommended as well both because the patient is incapable of checking some areas of the body, such as the scalp and back, and because the doctor has the skill and experience to know which spots are more likely to be malignant. 

Treatment for Skin Cancer

Treatment for skin cancer depends on the type, size and location of the tumor. Most options involve the removal of the entire growth. Removal procedures are usually simple, requiring only a local anesthetic in an outpatient setting. On occasion, depending on the size and location of the growth being removed, a skin graft from another region of the body may be required. Treatment options for skin cancer include the following:

  • Freezing (cryotherapy)
  • Excision
  • Laser therapy
  • Mohs surgery

Depending on the stage and severity of the skin cancer, in addition to excision of the growth, chemotherapy and/or radiation may be recommended.

Prevention of Skin Cancer

Although not every case of skin cancer can be prevented, the best way to avoid the problem is to protect skin from ultraviolet rays Recommendations for preventing skin cancer include the following:

  • Limit exposure to the skin, especially between 10 a.m. and 4 p.m.
  • Always wear sun screen with an SPF of at least 15
  • Wear a hat in the sun
  • Wear long sleeves and long pants
  • Avoid tanning beds and salons

Performing routine self-exams to spot skin changes, and seeing a dermatologist for a full-body screening on a regular basis, are also recommended.

Additional Resources