The skin is the body’s largest organ. It protects against heat, sunlight, injury, and infection. Skin also helps control body temperature and stores water, fat, and vitamin D. The skin has several layers, but the two main layers are the epidermis (upper or outer layer) and the dermis (lower or inner layer). Skin cancer begins in the epidermis, which is made up of three kinds of cells:
- Squamous cells: Thin, flat cells that form the top layer of the epidermis.
- Basal cells: Round cells under the squamous cells.
- Melanocytes: Cells that make melanin and are found in the lower part of the epidermis. Melanin is the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes make more pigment and cause the skin to darken.
Skin cancer can occur anywhere on the body, but it is most common in skin that is often exposed to sunlight, such as the face, neck, and hands.
Different types of cancer start in the skin.
Skin cancer may form in basal cells or squamous cells. Basal cell carcinoma and squamous cell carcinoma are the most common types of skin cancer. They are also called nonmelanoma skin cancer. Actinic keratosis is a skin condition that sometimes becomes squamous cell carcinoma.
Melanoma is less common than basal cell carcinoma or squamous cell carcinoma. It is more likely to invade nearby tissues and spread to other parts of the body.
Risk Factors.
Anything that increases a person's chance of getting a disease is called a risk factor. Not every person with one or more of these risk factors will develop skin cancer, and it will develop in people who don't have any known risk factors. Talk with your doctor if you think you may be at risk.
Risk factors for basal cell carcinoma and squamous cell carcinoma of the skin include the following:
- Being exposed to natural sunlight or artificial sunlight (such as from tanning beds) over long periods of time.
- Having a fair complexion, which includes the following:
- Fair skin that freckles and burns easily, does not tan, or tans poorly.
- Blue, green, or other light-colored eyes.
- Red or blond hair.
- Having a history of sunburns.
- Having a personal or family history of basal cell carcinoma, squamous cell carcinoma of the skin, actinic keratosis, familial dysplastic nevus syndrome, or unusual moles.
- Having certain changes in the genes or hereditary syndromes, such as basal cell nevus syndrome, that are linked to skin cancer.
- Having skin inflammation that has lasted for long periods of time.
- Having a weakened immune system.
- Being exposed to arsenic.
- Past treatment with radiation.
Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.
Changes in the Skin.
Not all changes in the skin are a sign of basal cell carcinoma, squamous cell carcinoma of the skin, or actinic keratosis. Check with your doctor if you notice any changes in your skin.
Signs of basal cell carcinoma and squamous cell carcinoma of the skin include the following:
- A sore that does not heal.
- Areas of the skin that are:
- Raised, smooth, shiny, and look pearly.
- Firm and look like a scar, and may be white, yellow, or waxy.
- Raised and red or reddish-brown.
- Scaly, bleeding, or crusty.
Basal cell carcinoma and squamous cell carcinoma of the skin occur most often in areas of the skin exposed to the sun, such as the nose, ears, lower lip, or top of the hands.
Signs of actinic keratosis include the following:
- A rough, red, pink, or brown, scaly patch on the skin that may be flat or raised.
- Cracking or peeling of the lower lip that is not helped by lip balm or petroleum jelly.
Actinic keratosis occurs most commonly on the face or the top of the hands.
Tests or procedures for diagnosis.
In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:
- Skin exam: An exam of the skin for bumps or spots that look abnormal in color, size, shape, or texture.
- Skin biopsy: All or part of the abnormal-looking growth is cut from the skin and viewed under a microscope by a pathologist to check for signs of cancer. There are four main types of skin biopsies:
- Shave biopsy: A sterile razor blade is used to “shave-off” the abnormal-looking growth.
- Punch biopsy: A special instrument called a punch or a trephine is used to remove a circle of tissue from the abnormal-looking growth.
- Incisional biopsy: A scalpel is used to remove part of a growth.
- Excisional biopsy: A scalpel is used to remove the entire growth.
Treatment depends on the type of skin cancer or other skin condition diagnosed:
Basal cell carcinoma
Basal cell carcinoma is the most common type of skin cancer. It usually occurs on areas of the skin that have been in the sun, most often the nose. Often this cancer appears as a raised bump that looks smooth and pearly. A less common type looks like a scar or it is flat and firm and may be skin-colored, yellow, or waxy. Basal cell carcinoma may spread to tissues around the cancer, but it usually does not spread to other parts of the body.
Squamous cell carcinoma
Squamous cell carcinoma occurs on areas of the skin that have been damaged by the sun, such as the ears, lower lip, and the back of the hands. Squamous cell carcinoma may also appear on areas of the skin that have been sunburned or exposed to chemicals or radiation. Often this cancer looks like a firm red bump. The tumor may feel scaly, bleed, or form a crust. Squamous cell tumors may spread to nearby lymph nodes. Squamous cell carcinoma that has not spread can usually be cured.
Actinic keratosis
Actinic keratosis is a skin condition that is not cancer, but sometimes changes into squamous cell carcinoma. One or more lesions may occur in areas that have been exposed to the sun, such as the face, the back of the hands, and the lower lip. It looks like rough, red, pink, or brown scaly patches on the skin that may be flat or raised, or as a cracked and peeling lower lip that is not helped by lip balm or petroleum jelly. Actinic keratosis may disappear without treatment.
There are different types of treatment for patients with basal cell carcinoma, squamous cell carcinoma of the skin, and actinic keratosis.
Different types of treatment are available for patients with basal cell carcinoma, squamous cell carcinoma of the skin, and actinic keratosis. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
The following types of treatment may be used:
Surgery
One or more of the following surgical procedures may be used to treat basal cell carcinoma, squamous cell carcinoma of the skin, or actinic keratosis:
- Simple excision: The tumor, along with some of the normal tissue around it, is cut from the skin.
- Mohs micrographic surgery: The tumor is cut from the skin in thin layers. During the procedure, the edges of the tumor and each layer of tumor removed are viewed through a microscope to check for cancer cells. Layers continue to be removed until no more cancer cells are seen. This type of surgery removes as little normal tissue as possible. It is often used to remove skin cancer on the face, fingers, or genitals and skin cancer that does not have a clear border. Mohs surgery. A surgical procedure to remove skin cancer in several steps. First, a thin layer of cancerous tissue is removed. Then, a second thin layer of tissue is removed and viewed under a microscope to check for cancer cells. More layers are removed one at a time until the tissue viewed under a microscope shows no remaining cancer. This type of surgery is used to remove as little normal tissue as possible and is often used to remove skin cancer on the face.
- Shave excision: The abnormal area is shaved off the surface of the skin with a small blade.
- Curettage and electrodesiccation: The tumor is cut from the skin with a curette (a sharp, spoon-shaped tool). A needle-shaped electrode is then used to treat the area with an electric current that stops the bleeding and destroys cancer cells that remain around the edge of the wound. The process may be repeated one to three times during the surgery to remove all of the cancer. This type of treatment is also called electrosurgery.
- Cryosurgery: A treatment that uses an instrument to freeze and destroy abnormal tissue, such as carcinoma in situ. This type of treatment is also called cryotherapy. An instrument with a nozzle is used to spray liquid nitrogen or liquid carbon dioxide to freeze and destroy abnormal tissue.
- Laser surgery: A surgical procedure that uses a laser beam (a narrow beam of intense light) as a knife to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.
- Dermabrasion: Removal of the top layer of skin using a rotating wheel or small particles to rub away skin cells.
Simple excision, Mohs micrographic surgery, curettage and electrodesiccation, and cryosurgery are used to treat basal cell carcinoma and squamous cell carcinoma of the skin. Laser surgery is rarely used to treat basal cell carcinoma. Simple excision, shave excision, curettage and desiccation, dermabrasion, and laser surgery are used to treat actinic keratosis.
Radiation therapy
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a machine outside the body to send radiation toward the area of the body with cancer.
External radiation therapy is used to treat basal cell carcinoma and squamous cell carcinoma of the skin.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing.
Chemotherapy for basal cell carcinoma, squamous cell carcinoma of the skin, and actinic keratosis is usually topical (applied to the skin in a cream or lotion). Topical fluorouracil (5-FU) is used to treat basal cell carcinoma.
Photodynamic therapy
Photodynamic therapy (PDT) is a cancer treatment that uses a drug and a certain type of light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein or put on the skin. The drug collects more in cancer cells than in normal cells. For skin cancer, laser light is shined onto the skin and the drug becomes active and kills the cancer cells. Photodynamic therapy causes little damage to healthy tissue.
Immunotherapy
Immunotherapy is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer.
Targeted therapy
Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells.
Chemical peel
A chemical peel is a procedure used to improve the way certain skin conditions look. A chemical solution is put on the skin to dissolve the top layers of skin cells. Chemical peels may be used to treat actinic keratosis. This type of treatment is also called chemabrasion and chemexfoliation.
Other drug therapy
Retinoids (drugs related to vitamin A) are sometimes used to treat squamous cell carcinoma of the skin. Diclofenac and ingenol are topical drugs used to treat actinic keratosis.
For more information, visit Cancer.gov
Source: PDQ® Adult Treatment Editorial Board. PDQ Breast Cancer Treatment. Bethesda, MD: National Cancer Institute. This information should not be used to make decisions about insurance reimbursement.