The skin is the largest organ in our body. It provides protection against heat, cold, light, and infection. The skin is made up of two major layers (epidermis and dermis) as well as various types of cells. The top (or outer) layer of the skin—the epidermis—is comprised of three cell types: flat, scaly cells on the surface called squamous cells; round cells called basal cells; and melanocytes which are cells that provide skin its pigment and protect against skin damage. The inner layer of the skin—the dermis—is the layer that contains the nerves, blood vessels, and sweat glands.

What Is Skin Cancer?

Skin cancer is a disease in which cancer (malignant) cells are found in the outer layers of your skin. There are several types of cancer that originate in the skin. The most common types are basal cell carcinoma (70% of all skin cancers) and squamous cell carcinoma (20% of all skin cancers). These types are classified as nonmelanoma skin cancer.

Melanoma (5% of all skin cancer) is the third major type of skin cancer. It is less common than basal cell or squamous cell skin cancer, but much more serious. Other types of skin cancer are rare.

Basal Cell Carcinoma

Basal cell carcinoma is the most common type of skin cancer. It typically appears as a small raised bump that has a pearly appearance. They are most commonly seen on areas of the skin that have received excessive sun exposure. These cancers may spread to the skin around the cancer but rarely spread to other parts or tissues in the body.

Squamous Cell Carcinoma

Squamous cell carcinoma is also seen on the areas of the body that have been exposed to excessive sun (nose, lower lip, hands, and forehead). Often this cancer appears as a firm red bump or ulceration of the skin that does not heal. Squamous cell carcinomas can spread to lymph nodes in the area.


Melanoma is a skin cancer that arises from the melanocytes in the skin. These cancers typically present as pigmented (colored) lesions in the skin with an irregular shape, irregular border, and multiple colors. It is the most harmful of all the skin cancers because it can spread (metastasize) to other sites in the body. Fortunately, most melanomas are curable when identified and treated early.

Who Gets Skin Cancer?

Skin cancer is a disease that has shown a steady increase over the last 20 years. Fortunately, with early diagnosis and treatment, it remains a very curable disease. A variety of factors have been identified which place a person at a higher risk to develop skin cancer.

(see “Am I at risk?” section below)

How Is Skin Cancer Diagnosed?

The most important first step is early diagnosis. The vast majority of skin cancers can be cured if diagnosed and treated early. Early signs of skin cancer include:

  • Skin sores that do not heal
  • Bumps or nodules in the skin that are enlarging
  • Changes in existing moles (size, texture, color)

If you notice any of the factors listed above see your doctor. If you have a spot or lump on your skin, your doctor may remove the growth and examine the tissue under the microscope. This is called a biopsy. A biopsy can usually be done in the doctor’s office after numbing the skin with a local anesthetic. Examination of the biopsy under the microscope will tell the doctor if the skin lesion is a cancer (malignancy).

How Is Skin Cancer Treated?

There are varieties of treatments available (including surgery, radiation therapy, and chemotherapy) to treat skin cancer. Treatment for skin cancer depends on the type and size of cancer, your age, and your overall health.

Surgery is the most common form of treatment. This generally consists of an office or outpatient procedure to excise the lesion and check edges to make sure all the cancer was removed. In many cases, the site is then repaired with simple stitches (primary closure). In larger skin cancers, your doctor may take some skin from another body site to cover the wound and promote healing. This is called skin grafting. In more advanced cases of skin cancer, radiation therapy or chemotherapy may be used in conjunction with surgery to improve cure rates. Your overall treatment will be individualized based on the type and size of skin cancer, your age, and your overall health.

How Can I Lower My Risk?

The single most important thing you can do to lower your risk of skin cancer is to avoid direct sun exposure. Sunlight produces ultraviolet (UV) radiation that can directly damage the DNA in our skin cells. People who work outdoors (farmers, construction, outdoor sports) are at the highest risk of developing a skin cancer. The sun’s rays are the most powerful between 10 am and 2 pm, so you must be particularly careful during those hours.

If you must be out during the day, wear clothing that covers as much of your skin as possible including a wide-brimmed hat to block the sun from your face, scalp, neck, and ears. In addition to protective clothing, the use of a sunscreen can reflect light away from the skin and provide protection against UV radiation. When selecting a sunscreen, choose one with a Sun Protection Factor (SPF) of 15 or more. Sunscreen products do not completely block the damaging rays but they do allow you to be in the sun longer without getting sunburned.

In addition to being sun-smart, it is critical to recognize early signs of trouble on your skin. The best time to do self-examination is after a shower in front of a full-length mirror. Note any moles, birthmarks, and blemishes. Be on the alert for sores that do not heal or new nodules on the skin. Any mole that changes in size, color, or texture should be carefully examined. If you notice anything new or unusual, see your physician right away. Catching skin cancer early can save your life.

Prevent Skin Cancer

  • Avoid sun in midday
  • Wear sunscreen all year, especially on your face
  • Wear protective clothing
  • Do not use tanning beds
  • Be aware of how your medications affect sun absorption
  • Perform frequent self-checks
  • If you are high-risk, visit a dermatologist regularly

Am I at risk?

People with any of the factors listed below have a higher risk of developing skin cancer and should be particularly careful of sun exposure.

  • Long-term sun exposure
  • Fair skin (typically blonde or red hair with freckles)
  • Place of residence (increased risk in more Southern climates)
  • Presence of moles with irregular edges, uneven coloring, and increasing size > 6 mm
  • Family history of skin cancer
  • Use of indoor tanning devices
  • Severe sunburns as a child
  • Nonhealing ulcers or nodules in the skin
  • A weakened immune system
  • Excessive sun exposure, especially those who work out of doors
  • Exposure to radiation
  • Living at high elevation

When It Is Time to See a Doctor

If you notice any of the following changes to your skin, make an appointment with your doctor to have it looked at.

  • Small, scaly patches (keratosis)
  • Swelling, darkening, and hardening of the lower lip
  • Cutaneous “horns”
  • Non-healing sores
  • White, waxy “scar-like” formations
  • New, red scaly patch on the skin
  • Irregular moles – remember ABCDE:
    • Asymmetry
    • Irregular Border
    • Color – those that are multi-colored, red, blue, or black
    • Diameter – larger than 6mm
    • Evolution – enlargement or new changes
  • Symptomatic moles
    • Itching
    • Painful
    • Bleeding
    • Crusting
    • Oozing
    • Swelling

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