Skin Cancer

Skin cancer is the abnormal growth of skin cells. It most often develops on skin that is exposed to the sun, it can also occur on areas of your skin not ordinarily exposed to sunlight.

The skin is the largest organ in the body and it protects against heat, sunlight, injury, and infection. Skin also helps control body temperature and stores water and fat.

Skin cancer is the most common of all cancers, and there are three major types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma. Rare types of skin cancer include Merkel cell carcinoma, skin lymphoma, and Kaposi sarcoma. Basal cell cancer and squamous cell cancer usually form on the head, face, neck, hands, and arms. Melanoma is more dangerous than carcinomas, but it is less common. Approximately 3.5 million cases of basal and squamous cell skin cancer are diagnosed in the United States each year. Melanoma, a more dangerous type of skin cancer, accounts for more than 73,000 cases of skin cancer per year.

You can reduce your risk of skin cancer by limiting or avoiding exposure to ultraviolet (UV) radiation. Checking your skin for suspicious changes can help detect skin cancer at its earliest stages. Early detection of skin cancer gives you the greatest chance for successful skin cancer treatment. If not treated, some types of skin cancer cells can spread to other tissues and organs. Treatments include surgery, radiation therapy, chemotherapy, photodynamic therapy (PDT), and biologic therapy.

Skin cancer develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women. But it can also form on other areas of the body, including your palms, beneath your fingernails or toenails, and your genital area. Skin cancer affects people of all skin tones, including those with darker complexions.

If you notice any of the following signs or symptoms of skin cancer, see a healthcare provider right away:

• any change on your skin, especially in the size or color of a mole, growth, or spot, or a new growth (even if it has no color)
• scaliness, roughness, oozing, bleeding, or a change in the way an area of skin looks
• a sore that does not heal
• the spread of pigmentation (color) beyond its border, such as dark coloring that spreads past the edge of a mole or mark
• a change in sensation, such as itchiness, tenderness, or pain

Basal cell carcinoma usually occurs in sun-exposed areas of your body, such as your neck or face. Signs and symptoms of basal cell carcinoma include:

• a pearly or waxy bump
• a flat, flesh-colored or brown scar-like lesion

Squamous cell carcinoma also commonly occurs on sun-exposed areas of your body, such as your face, ears, and hands. Signs and symptoms of squamous cell carcinoma include:

• a firm, red nodule
• a flat lesion with a scaly, crusted surface

Melanoma can develop anywhere on your body, in otherwise normal skin, or in an existing mole that becomes cancerous. Melanoma most often appears on the face or the trunk of affected men. In women, this type of cancer most often develops on the lower legs. In both men and women, melanoma can occur on skin that has not been exposed to the sun. Melanoma can affect people of any skin tone. In people with darker skin tones, melanoma tends to occur on the palms or soles, or under the fingernails or toenails.

Signs and symptoms of melanoma include:

• a large brownish spot with darker speckles
• a mole that changes in color, size or feel or that bleeds
• a small lesion with an irregular border and portions that appear red, white, blue or blue-black
• dark lesions on your palms, soles, fingertips or toes, or on mucous membranes lining your mouth, nose, vagina or anus

Skin cancer occurs when errors (mutations) occur in the DNA of skin cells. The mutations cause the cells to grow out of control and form a mass of cancer cells.

Skin cancer begins in your skin's top layer — the epidermis. The epidermis is a thin layer that provides a protective cover of skin cells that your body continually sheds. The epidermis contains three main types of cells:

• squamous cells, which lie just below the outer surface and function as the skin's inner lining
• basal cells, which sit beneath the squamous cells and produce new skin cells
• melanocytes, which are located in the lower part of your epidermis and produce melanin, the pigment that gives skin its normal color

Much of the damage to DNA in skin cells results from ultraviolet (UV) radiation found in sunlight and in the lights used in tanning beds. However, sun exposure does not explain skin cancers that develop on skin not ordinarily exposed to sunlight. This indicates that other factors may contribute to your risk of skin cancer, such as being exposed to toxic substances or having a condition that weakens your immune system.

Risk factors for skin cancer include:

• too much exposure to ultraviolet (UV) radiation (from sunlight or tanning beds and lamps)
• fair or pale skin (easily sunburned, doesn’t tan much or at all, natural red or blond hair)
• exposure to large amounts of coal tar, paraffin, arsenic compounds, or certain types of oil
• family history of skin cancers
• multiple or unusual moles
• severe sunburns in the past
• weakened immune system
• older age (although melanomas can also occur in younger people)

To diagnose skin cancer, your doctor will examine your skin. He or she will look at your skin to determine whether your skin changes are likely to be skin cancer. Further testing may be needed to confirm that diagnosis. He or she may also remove a sample of suspicious skin for testing (skin biopsy). A biopsy can determine whether you have skin cancer and, if so, what type of skin cancer you have.

Most skin cancers are preventable. To protect yourself, follow these skin cancer prevention tips:

Avoid the sun during the middle of the day. For many people in North America, the sun's rays are strongest between about 10 a.m. and 4 p.m. Schedule outdoor activities for other times of the day, even in winter or when the sky is cloudy. You absorb UV radiation year-round, and clouds offer little protection from damaging rays. Avoiding the sun at its strongest helps you avoid the sunburns and suntans that cause skin damage and increase your risk of developing skin cancer. Sun exposure accumulated over time also may cause skin cancer.

Wear sunscreen year-round. Sunscreens do not filter out all harmful UV radiation, especially the radiation that can lead to melanoma. But they play a major role in an overall sun protection program. Use a broad-spectrum sunscreen with an SPF of at least 15. Use a generous amount of sunscreen on all exposed skin, including your lips, the tips of your ears, and the backs of your hands and neck.

Wear protective clothing. Sunscreens do not provide complete protection from UV rays, so cover your skin with dark, tightly woven clothing that covers your arms and legs, and a broad-brimmed hat, which provides more protection than a baseball cap or visor does.

Avoid tanning beds. Lights used in tanning beds emit UV rays and can increase your risk of skin cancer.

Be aware of sun-sensitizing medications. Some common prescription and over-the-counter drugs, including antibiotics, can make your skin more sensitive to sunlight. Ask your doctor or pharmacist about the side effects of any medications you take. If they increase your sensitivity to sunlight, take extra precautions to stay out of the sun in order to protect your skin.

Check your skin regularly and report changes to your doctor. Examine your skin often for new skin growths or changes in existing moles, freckles, bumps and birthmarks.

If you have or have had skin cancer, you can take steps to manage the stress that accompanies the diagnosis.

• Learn about skin cancer so you can make informed decisions about your care.
• Have a schedule of follow-up tests and go to each appointment.
• Take care of yourself so that you are ready to fight cancer. This includes eating a healthy that includes plenty of fruits, vegetables and whole grains, exercising for at least 30 minutes most days of the week, and getting enough sleep so that you wake feeling rested.
• Accept help and support from family and friends.

Your treatment options for skin cancer will vary, depending on the size, type, depth, and location of the lesions. Small skin cancers limited to the surface of the skin may not require treatment beyond an initial skin biopsy that removes the entire growth.

If not treated, however, some types of skin cancer cells can spread to other tissues and organs. Treatments include surgery, radiation therapy, chemotherapy, photodynamic therapy, and biologic therapy.

Radiation therapy. Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation therapy may be an option when cancer can't be completely removed during surgery.

Photodynamic therapy. This treatment destroys skin cancer cells with a combination of laser light and drugs that makes cancer cells sensitive to light.

Chemotherapy. In chemotherapy, drugs are used to kill cancer cells. For cancers limited to the top layer of skin, creams or lotions containing anti-cancer agents may be applied directly to the skin. Systemic chemotherapy can be used to treat skin cancers that have spread to other parts of the body. Chemotherapy agents approved for skin cancer include:

• aldesleukin (IL-2, interleukin-2, Proleukin)
• dacarbazine (DTIC-Dome)
• fluorouracil (Adrucil, Efudex, 5-FU, Fluoroplex)
• imiquimod (Aldara)

Biological therapy. Biological therapy uses your body's immune system to kill cancer cells. Biologic therapies used for skin cancers include:

• cobimetinib (Cotellic)
• dabrafenib (Tafinlar)
• ipilimumab (Yervoy)
• nivolumab (Opdivo)
• peginterferon Alfa-2b (Sylatron)
• pembrolizumab (Keytruda)
• recombinant Interferon Alfa-2b (Intron A)
• sonidegib (Odomzo)
• trametinib (Mekinist)
• vemurafenib (Zelboraf)
• vismodegib (Erivedge)