• Skin Cancer—Overview

    (Basal Cell Carcinoma; Squamous Cell Carcinoma)


    Skin cancer is when cancer cells grow in the skin.
    The two most common kinds of skin cancer are:
    • Basal cell carcinoma—This is a slow-growing cancer. It begins in the inner part of the outer layer of the skin. This type rarely spreads to other parts of the body. It accounts for almost all skin cancers in the United States.
    • Squamous cell carcinoma—This type of cancer starts in the outer layer of the skin. It rarely spreads. However, it spreads more often than basal cell carcinoma.
    Basal Cell Carcinoma
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    Cancer occurs when cells in the body divide without control or order. In this case, the cells are skin cells. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms. This is called a growth or tumor. The term malignant refers to tumors that are cancer. Malignant tumors can invade nearby tissues and spread to other parts of the body. A benign tumor is unable to invade or spread.
    It is important that skin cancers be found and treated early. They can quickly invade and destroy nearby tissue. Another type of cancer that occurs in the skin is melanoma. There are also rare forms of skin cancer. These include merkel cell carcinoma, sebaceous carcinoma, and eccrine carcinoma.


    Ultraviolet radiation from the sun is the main cause of skin cancer. Some people are at greater risk because of their genetics. Artificial radiation from sun lamps and tanning booths can also cause skin cancer.
    Actinic keratosis is a precancerous lesion. It is caused by accumulated exposure to ultraviolet radiation from the sun. If left untreated, it may progress to squamous cell carcinoma (rare).

    Risk Factors

    A risk factor is something that increases your chance of getting a disease or condition.
    Risk factors include:
    • Fair skin that freckles easily
    • Red or blonde hair
    • Light-colored eyes
    • Age: 50 or older
    • Sex: male
    • Race: White people who live in places where the sun's rays are strong year-round
    • Excessive sun exposure without protective clothing or sunscreen
    • Frequent use of tanning beds
    • Exposure to arsenic, industrial tar, coal, paraffin, and certain types of oil (for squamous cell carcinoma)
    • Radiation treatment
    • Light treatments for psoriasis, especially psoralen ultraviolet A (PUVA)
    • Chronic, nonhealing wounds (for squamous cell carcinoma)
    • Certain genetic diseases, such as basal cell nevus syndrome or xeroderma pigmentosum


    Most skin cancers are not painful. The most common first symptom of skin cancer is a change in the skin. This could be a new growth or a sore that doesn't heal. When it starts, skin cancer may appear as:
    • A small, smooth, shiny, pale, or waxy lump
    • A firm, red lump
    • A lump that bleeds or develops a crust
    • A flat, red spot that is rough, dry, or scaly
    Skin cancers are found mainly on areas exposed to the sun:
    • Head
    • Face
    • Ears
    • Neck
    • Hands
    • Arms
    However, skin cancer can occur anywhere.
    These symptoms may also be caused by other, less serious health conditions. See your doctor if you experience these symptoms for more than two weeks.


    Your doctor will ask about your symptoms and medical history. A physical exam will be done. If you have a growth like those listed above, your doctor may treat it in the office. This involves removing all or part of the lesion. It will then be sent to a laboratory for a biopsy.
    In cases where the growth is very large, or has been present for a long time, the doctor will carefully check the lymph nodes in the area. You may also need to have more tests. They will determine if cancer has spread to other parts of the body.


    Treatment for skin cancer usually involves surgery. In some cases, radiation therapy or chemotherapy may be used. Sometimes a combination of methods is used.
    Treatments include:


    Many skin cancers can be cut from the skin quickly and easily. In fact, the cancer is sometimes completely removed during biopsy, and no further treatment is needed. Surgical techniques include:
    Curettage and Electrodesiccation
    This involves scooping the cancer out with a curette (an instrument with a sharp, spoon-shaped end). The area is treated with an electric current to control bleeding. This also kills any cancer cells remaining around the edge of the wound. This technique is used for very small or superficial cancers.
    Mohs Surgery
    Mohs surgery is the removal of all of the cancerous tissue. The surgeon will try to remove as little healthy tissue as possible. This method is used to remove:
    • Large tumors
    • Tumors in hard-to-treat places
    • Tumors of undetermined shape and depth
    • Cancers that have recurred
    The procedure is done by specially trained dermatologic Mohs surgeons. The cancer is shaved off one thin layer at a time. Each layer is checked under a microscope for cancer cells until the entire tumor is removed. This method offers the highest chance of a cure.
    Liquid nitrogen is used to freeze and kill the abnormal cells. After the area thaws, the dead tissue falls off. More than one freezing may be needed to remove the growth completely. This method may be used to treat precancerous skin conditions (actinic keratoses) and certain small or superficial skin cancers.

    Laser Therapy

    Laser therapy uses a narrow beam of light to remove or destroy cancer cells. This method is sometimes used for cancers in the outer layer of skin.

    Radiation Therapy (Radiotherapy)

    Radiation therapy uses radiation to kill cancer cells and shrink tumors.

    Topical Chemotherapy

    Topical chemotherapy is the use of drugs to kill cancer cells. The drugs can be creams or lotions. This method is successful in treating precancerous conditions and cancers limited to the outer layer of the skin. The most common topical chemotherapy used is a form of 5-fluorouracil (5-FU) or imiquimod cream.


    • Avoid spending too much time in the sun.
    • Protect your skin from the sun with clothing. Wear a shirt, sunglasses, and a hat with a broad brim.
    • Use sunscreens with a sun protection factor (SPF) of 15 or more on skin that will be exposed to the sun.
    • Avoid exposing your skin to the sun between 10:00 AM and 2:00 PM standard time, or 11:00 AM to 3:00 PM daylight saving time.
    • Don't use sun lamps or tanning booths.
    Take the following precautions to find skin cancer early:
    • If you have any of the symptoms listed above, have your skin examined by a doctor.
    • If you have fair skin, have your skin checked by a doctor.
    • Learn how to do a skin self-exam.


    American Academy of Dermatology http://www.aad.org

    American Cancer Society http://www.cancer.org

    American College of Mohs Surgery http://mohscollege.org

    Skin Cancer Foundation http://www.skincancer.org


    Canadian Cancer Society http://www.cancer.ca

    Canadian Dermatology Association http://www.dermatology.ca


    Overview: skin cancer—basal and squamous cell. American Cancer Society website. Available at: http://www.cancer.org/cancer/skincancer-basalandsquamouscell/index. Accessed June 22, 2008.

    Skin cancer. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/types/skin. Accessed June 22, 2008.

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