What is skin cancer?

Skin cancer is a tumor or growth of abnormal cells in our skin. The most common type of skin cancer is basal cell carcinoma, followed by squamous cell carcinoma, and then melanoma.

When found early, these skin cancers can be cured. The most serious type of skin cancer is called malignant melanoma. Malignant melanomas are more likely to spread, causing significant morbidity and mortality (illness and death).

Skin cancer is the most commonly diagnosed cancer in humans. Because skin cancer can be identified and treated early, most are cured. If it is neglected, skin cancer can be deadly. For most people, skin cancer is a preventable disease; therefore, by taking a few safeguards, you can reduce your risk and even prevent skin cancer.

What are the signs of skin cancer?

Skin cancer can be a spot that does not heal. If you scrap your knee, it will usually heal within a month. Skin cancer will not heal.

Skin cancers can appear as moles, scaly patches, open sores, or raised bumps. These signs can vary, depending on the form of skin cancer. Different types of skin cancer share some of the same signs, so it's important to get any moles or bumps of concern checked. Here are some signs to look for:

Signs of skin cancer (ABCDE):

(A) Asymmetry: irregular shape
(B) Border: blurry or irregularly shaped edges
(C) Color: mole with more than one color
(D) Diameter: larger than a pencil eraser (6 mm)
(E) Evolution: enlarging, changing in shape, color, or size. (This is the most important sign.)

Who is most at risk for skin cancer?

The following are most at risk for skin cancer:

  • People who tan or use tanning beds
  • People who get sunburned
  • People with light skin
  • People with many freckles or moles
  • People with a family history of skin cancer
  • People with blue eyes

How can I know if I have skin cancer?

If you have a mole or other skin lesion that is causing you concern, show it to your health care provider. He or she will check your skin and may ask you to see another doctor to have the lesion further evaluated. If needed to help with the diagnosis, the doctor can take a biopsy (remove a small sample) and send it to a laboratory to be examined under a microscope. The doctor will be able to call you with the results in about a week.

How is skin cancer treated?

Skin cancer is treated by removing the lesion and a part of the normal skin surrounding it. First, the area is numbed with medicine. A scalpel is used to remove the skin cancer.

The procedure is often performed in the doctor's office. Other treatments include freezing (cryotherapy), scraping and burning (electrodessication and curettage), and radiation therapy.

If lesions are larger and more likely to return, the doctor may cut out sections of the tumor and view these sections under a microscope (Mohs surgery). The earlier skin cancer is removed, the better your chances for a full recovery.

Can skin cancer be prevented?

In most cases, skin cancer can be prevented. The best way to protect yourself is to avoid too much sunlight and sunburns. Ultraviolet (UV) rays from the sun damage the skin, and over time lead to skin cancer.

Here are ways to protect yourself from skin cancer:

  • Seek shade. Don't spend long periods of time (more than an hour) in direct sunlight.
  • Wear hats with wide brims to protect your face and ears.
  • Wear long-sleeved shirts and pants to protect your arms and legs.
  • Use broad-spectrum sunscreens with an SPF (skin protection factor) of 30 or higher that protect against burning and tanning rays. Apply the sunscreen 30 minutes before you go outside. (Broad-spectrum sunscreens protect against UV-B and UV-A rays.)
  • Wear sunglasses to protect your eyes.
  • Use a lip balm with sunscreen.
  • Avoid the sun between 10:00 a.m. and 4:00 p.m.
  • Show any changing mole to your health care provider.

Where can I learn more about skin cancer?

National Cancer Institute-Cancer Information Service
1,800.4.CANCER (422.6237)

American Academy of Dermatology
1.888.462.DERM (3376)


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 1/9/2017...#4581