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What Is Cancer?
Types of Skin Cancer
Cause and Prevention
Detection and Diagnosis
Treating Skin Cancer
Curettage and Electrodesiccation
Questions To Ask the Doctor
Skin Cancer Research
How To Do a Skin Self-Exam
National Cancer Institute Information Resources
Each year, about a million people in the United States learn that they have skin cancer. This National Cancer Institute (NCI) booklet will give you some important information about this disease. It explains how skin cancer is diagnosed and treated and has information about preventing this disease.
Words that may be new to readers appear in italics. Definitions of these words and other terms related to skin cancer can be found in the Dictionary. For some words, a "sounds-like" spelling is also given.
Other NCI booklets are listed in the Other Booklets section. Our materials cannot answer every question you may have about skin cancer. They cannot take the place of talks with doctors, nurses, and other members of the health care team. We hope our information will help with those talks.
Research has led to better methods of diagnosing and treating this disease. It is encouraging to know that skin cancer is now almost 100 percent curable if found early and treated promptly.
Our knowledge about skin cancer and other types of cancer is
increasing rapidly. For up-to-date information or to order this publication,
call the NCI-supported Cancer Information
Service (CIS) toll free at 1-800-4-CANCER (1-800-422-6237).
The skin is the body's outer covering. It protects us against heat, light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers: the outer epidermis and the inner dermis.
The epidermis (outer layer of the skin) is mostly made up of flat, scale-like cells called squamous cells. Under the squamous cells are round cells called basal cells. The deepest part of the epidermis also contains melanocytes. These cells produce melanin, which gives the skin its color.
The dermis (inner layer of skin) contains blood and lymph
vessels, hair follicles, and
glands. These glands produce sweat, which helps regulate body temperature, and
sebum, an oily substance that helps keep
the skin from drying out. Sweat and sebum reach the skin's surface through tiny
openings called pores.
What Is Cancer?
Cancer is a group of more than 100 diseases. Although each type of cancer differs from the others in many ways, every cancer is a disease of some of the body's cells.
Healthy cells that make up the body's tissues grow, divide, and replace themselves in an orderly way. This process keeps the body in good repair. Sometimes, however, normal cells lose their ability to limit and direct their growth. They divide too rapidly and grow without any order. Too much tissue is produced, and tumors begin to form. Tumors can be benign or malignant.
Types of Skin Cancer
The two most common kinds of skin cancer are basal cell carcinoma and squamous cell carcinoma. (Carcinoma is cancer that begins in the cells that cover or line an organ.) Basal cell carcinoma accounts for more than 90 percent of all skin cancers in the United States. It is a slow-growing cancer that seldom spreads to other parts of the body. Squamous cell carcinoma also rarely spreads, but it does so more often than basal cell carcinoma. However, it is important that skin cancers be found and treated early because they can invade and destroy nearby tissue.
Basal cell carcinoma and squamous cell carcinoma are sometimes
called nonmelanoma skin
cancer. Another type of cancer that occurs in the skin is melanoma, which begins in the melanocytes.
More information about this disease can be found in the booklet What You Need To
Know About Melanoma.
Cause and Prevention
Skin cancer is the most common type of cancer in the United States. According to current estimates, 40 to 50 percent of Americans who live to age 65 will have skin cancer at least once. Although anyone can get skin cancer, the risk is greatest for people who have fair skin that freckles easily--often those with red or blond hair and blue or light-colored eyes.
Ultraviolet (UV) radiation from the sun is the main cause of skin cancer. (Two types of ultraviolet radiation--UVA and UVB--are explained in the ultraviolet (UV) radiation definition in the Dictionary.) Artificial sources of UV radiation, such as sunlamps and tanning booths, can also cause skin cancer.
The risk of developing skin cancer is affected by where a person lives. People who live in areas that get high levels of UV radiation from the sun are more likely to get skin cancer. In the United States, for example, skin cancer is more common in Texas than it is in Minnesota, where the sun is not as strong. Worldwide, the highest rates of skin cancer are found in South Africa and Australia, areas that receive high amounts of UV radiation.
In addition, skin cancer is related to lifetime exposure to UV radiation. Most skin cancers appear after age 50, but the sun's damaging effects begin at an early age. Therefore, protection should start in childhood to prevent skin cancer later in life.
Whenever possible, people should avoid exposure to the midday sun (from 10 a.m. to 2 p.m. standard time, or from 11 a.m. to 3 p.m. daylight saving time). Keep in mind that protective clothing, such as sun hats and long sleeves, can block out the sun's harmful rays. Also, lotions that contain sunscreens can protect the skin. Sunscreens are rated in strength according to a sun protection factor (SPF), which ranges from 2 to 30 or higher. Those rated 15 to 30 block most of the sun's harmful rays.
NCI is supporting research to try to find new ways to prevent
skin cancer. This research involves people who have a high risk of developing
skin cancer--those who have already had the disease and those who have certain
other rare skin diseases that increase their risk of skin cancer.
The most common warning sign of skin cancer is a change on the skin, especially a new growth or a sore that doesn't heal. Skin cancers don't all look the same. For example, the cancer may start as a small, smooth, shiny, pale, or waxy lump. Or it can appear as a firm red lump. Sometimes, the lump bleeds or develops a crust. Skin cancer can also start as a flat, red spot that is rough, dry, or scaly.
Both basal and squamous cell cancers are found mainly on areas of the skin that are exposed to the sun--the head, face, neck, hands, and arms. However, skin cancer can occur anywhere.
Actinic keratosis, which appears as rough, red or brown scaly patches on the skin, is known as a precancerous condition because it sometimes develops into squamous cell cancer. Like skin cancer, it usually appears on sun-exposed areas but can be found elsewhere.
Changes in the skin are not sure signs of cancer; however, it is important to see a doctor if any symptom lasts longer than 2 weeks. Don't wait for the area to hurt--skin cancers seldom cause pain.
Detection and Diagnosis
The cure rate for skin cancer could be 100 percent if all skin cancers were brought to a doctor's attention before they had a chance to spread. Therefore, people should check themselves regularly for new growths or other changes in the skin. Any new, colored growths or any changes in growths that are already present should be reported to the doctor without delay. (See the How To Do a Skin Self-Exam section for a simple guide on how to do a skin self-exam.)
Doctors should also look at the skin during routine physical exams. People who have already had skin cancer should be sure to have regular exams so that the doctor can check the skin--both the treated areas and other places where cancer may develop.
Basal cell carcinoma and squamous cell carcinoma are generally diagnosed and treated in the same way. When an area of skin does not look normal, the doctor may remove all or part of the growth. This is called a biopsy. To check for cancer cells, the tissue is examined under a microscope by a pathologist or a dermatologist. A biopsy is the only sure way to tell if the problem is cancer.
Doctors generally divide skin cancer into two stages: local
(affecting only the skin) or metastatic (spreading beyond the skin). Because
skin cancer rarely spreads, a biopsy often is the only test needed to determine
the stage. 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. In addition, the
patient may need to have additional tests, such as special x-rays, to find out
whether the cancer has spread to other parts of the body. Knowing the stage of
a skin cancer helps the doctor plan the best treatment.
In treating skin cancer, the doctor's main goal is to remove or destroy the cancer completely with as small a scar as possible. To plan the best treatment for each patient, the doctor considers the location and size of the cancer, the risk of scarring, and the person's age, general health, and medical history.
It is sometimes helpful to have the advice of more than one doctor before starting treatment. It may take a week or two to arrange for a second opinion, but this short delay will not reduce the chance that treatment will be successful. There are a number of ways to find a doctor for a second opinion:
Treating Skin Cancer
Many skin cancers can be cut from the skin quickly and easily. In fact, the cancer is sometimes completely removed at the time of the biopsy, and no further treatment is needed.
Curettage and Electrodesiccation
Doctors commonly use a type of surgery called curettage. After a local anesthetic numbs the area, the cancer is scooped out with a curette, an instrument with a sharp, spoon-shaped end. The area is also treated by electrodesiccation. An electric current from a special machine is used to control bleeding and kill any cancer cells remaining around the edge of the wound. Most patients develop a flat, white scar.
Mohs' technique is a special type of surgery used for skin cancer. Its purpose is to remove all of the cancerous tissue and as little of the healthy tissue as possible. It is especially helpful when the doctor is not sure of the shape and depth of the tumor. In addition, this method is used to remove large tumors, those in hard-to-treat places, and cancers that have recurred. The patient is given a local anesthetic, and the cancer is shaved off one thin layer at a time. Each layer is checked under a microscope until the entire tumor is removed. The degree of scarring depends on the location and size of the treated area. This method should be used only by doctors who are specially trained in this type of surgery.
Extreme cold may be used to treat precancerous skin conditions, such as actinic keratosis, as well as certain small skin cancers. In cryosurgery, liquid nitrogen is applied to the growth 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. Cryosurgery usually does not hurt, but patients may have pain and swelling after the area thaws. A white scar may form in the treated area.
Laser therapy uses a narrow beam of light to remove or destroy cancer cells. This approach is sometimes used for cancers that involve only the outer layer of skin.
Sometimes, especially when a large cancer is removed, a skin graft is needed to close the wound and reduce the amount of scarring. For this procedure, the doctor takes a piece of healthy skin from another part of the body to replace the skin that was removed.
Skin cancer responds well to radiation therapy (also called radiotherapy), which uses high-energy rays to damage cancer cells and stop them from growing. Doctors often use this treatment for cancers that occur in areas that are hard to treat with surgery. For example, radiation therapy might be used for cancers of the eyelid, the tip of the nose, or the ear. Several treatments may be needed to destroy all of the cancer cells. Radiation therapy may cause a rash or make the skin in the area dry or red. Changes in skin color and/or texture may develop after the treatment is over and may become more noticeable many years later.
Topical chemotherapy is the use of anticancer drugs in a cream or lotion applied to the skin. Actinic keratosis can be treated effectively with the anticancer drug fluorouracil (also called 5-FU). This treatment is also useful for cancers limited to the top layer of skin. The 5-FU is applied daily for several weeks. Intense inflammation is common during treatment, but scars usually do not occur.
In clinical trials (research studies with cancer patients), doctors are studying new treatments for skin cancer. For example, they are exploring photodynamic therapy, a treatment that destroys cancer cells with a combination of laser light and drugs that make the cells sensitive to light. Biological therapy (also called immunotherapy) is a form of treatment to improve the body's natural ability to fight cancer. Interferon and tumor necrosis factor are types of biological therapy under study for skin cancer.
Even though most skin cancers are cured, the disease can recur in the same place. Also, people who have
been treated for skin cancer have a higher-than-average risk of developing a
new cancer elsewhere on the skin. That's why it is so important for them to
continue to examine themselves regularly, to visit their doctor for regular
checkups, and to follow the doctor's instructions on how to reduce the risk of
developing skin cancer again.
Questions To Ask the Doctor
Skin cancer has a better prognosis, or outcome, than most other types of cancer. Although skin cancer is the most common type of cancer in this country, it accounts for much less than 1 percent of all cancer deaths. It is cured in 85 to 95 percent of all cases. Still, any diagnosis of cancer can be frightening, and it's natural to have concerns about medical tests, treatments, and doctors' bills.
Patients have many important questions to ask about cancer, and their doctor is the best person to provide answers. Most people want to know exactly what kind of cancer they have, how it can be treated, and how successful the treatment is likely to be. The following are some other questions that patients might want to ask their doctor:
Some patients become concerned that treatment may change their
appearance, especially if the skin cancer is on their face. Patients should
discuss this important concern with their doctor. And they may want to have a
second opinion before treatment. (See the Treatment
Skin Cancer Research
Scientists at hospitals and research centers are studying the causes of skin cancer and looking for new ways to prevent the disease. They are also exploring ways to improve treatment.
When laboratory research shows that a new prevention or treatment method has promise, doctors use it with people in clinical trials. These trials are designed to answer scientific questions and to find out whether the new approach is both safe and effective. People who take part in clinical trials make an important contribution to medical science and may have the first chance to benefit from improved methods.
People interested in taking part in a trial should discuss this option with their doctor. Taking Part in Clinical Trials: What Cancer Patients Need To Know is a National Cancer Institute booklet that explains some of the possible benefits and risks of such studies.
One way to learn about clinical trials is through
PDQ, a computerized
resource developed by the National Cancer Institute. This resource contains
information about cancer treatment and about clinical trials in progress all
over the country. The Cancer Information Service can provide PDQ information to
patients and the public.
The National Cancer Institute booklets listed below are available free of charge by calling 1-800-4-CANCER.
How To Do a Skin Self-Exam
You can improve your chances of finding skin cancer promptly by performing a simple skin self-exam regularly.
The best time to do this self-exam is after a shower or bath. You should check your skin in a well-lighted room using a full-length mirror and a hand-held mirror. It's best to begin by learning where your birthmarks, moles, and blemishes are and what they usually look like. Check for anything new--a change in the size, texture, or color of a mole, or a sore that does not heal.
Check all areas, including the back, the scalp, between the buttocks, and the genital area.
By checking your skin regularly, you will become familiar with
what is normal. If you find anything unusual, see your doctor right away.
Remember, the earlier skin cancer is found, the better the chance for cure.
National Cancer Institute Information
You may want more information for yourself, your family, and your health care provider. The following National Cancer Institute (NCI) services are available to help you.
actinic keratosis (ak-TIN-ik ker-a-TOE-sis): A precancerous condition of thick, scaly patches of skin. Also called solar or senile keratosis.
anesthetics (an-es-THET-iks): Substances that cause loss of feeling or awareness. Local anesthetics cause loss of feeling in a part of the body. General anesthetics put the person to sleep.
basal cell carcinoma (BAY-sal sel kar-sin-O-ma): A type of skin cancer that arises from the basal cells, small round cells found in the lower part (or base) of the epidermis, the outer layer of the skin.
basal cells (BAY-sal): Small, round cells found in the lower part (or base) of the epidermis, the outer layer of the skin.
benign (beh-NINE): Not cancerous; does not invade nearby tissue or spread to other parts of the body.
biological therapy (by-o-LAHJ-i-kul): Treatment to stimulate or restore the ability of the immune system to fight infection and disease. Also used to lessen side effects that may be caused by some cancer treatments. Also known as immunotherapy, biotherapy, or biological response modifier (BRM) therapy.
biopsy (BY-ahp-see): A procedure used to remove cells or tissues to look at them under a microscope and check for signs of disease. When an entire tumor or lesion is removed, the procedure is called an excisional biopsy. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.
cancer: A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.
carcinoma (kar-sin-O-ma): Cancer that begins in the skin or in tissues that line or cover internal organs.
chemotherapy (kee-mo-THER-a-pee): Treatment with anticancer drugs.
clinical trial: A research study that tests how well new medical treatments or other interventions work in people. Each study is designed to test new methods of screening, prevention, diagnosis, or treatment of a disease.
cryosurgery (KRYE-o-SIR-jer-ee): Treatment performed with an instrument that freezes and destroys abnormal tissues. This procedure is a form of cryotherapy.
curettage (kyoo-reh-TAHZH): Removal of tissue with a curette, a spoon-shaped instrument with a sharp edge.
curette (kyoo-RET): A spoon-shaped instrument with a sharp edge.
dermatologist (der-ma-TAH-lo-jist): A doctor who specializes in the diagnosis and treatment of skin problems.
dermis (DER-mis): The lower or inner layer of the two main layers of tissue that make up the skin.
electrodesiccation (e-LEK-tro-des-ih-KAY-shun): The drying of tissue by a high-frequency electric current applied with a needle-shaped electrode.
epidermis (ep-i-DER-mis): The upper or outer layer of the two main layers of tissue that make up the skin.
fluorouracil (floor-o-YOOR-a-sil): An anticancer drug that belongs to the family of drugs called antimetabolites.
hair follicles (FOL-i-kuls): Shafts or openings on the surface of the skin through which hair grows.
interferon (in-ter-FEER-on): A biological response modifier (a substance that can improve the body's natural response to disease). Interferons interfere with the division of cancer cells and can slow tumor growth. There are several types of interferons, including interferon-alpha, -beta, and -gamma. These substances are normally produced by the body. They are also made in the laboratory for use in treating cancer and other diseases.
laser (LAY-zer): A device that concentrates light into an intense, narrow beam used to cut or destroy tissue. It is used in microsurgery, photodynamic therapy, and for a variety of diagnostic purposes.
lymph node: A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Also known as a lymph gland. Lymph nodes are spread out along lymphatic vessels and contain many lymphocytes, which filter the lymphatic fluid (lymph).
malignant (ma-LIG-nant): Cancerous; a growth with a tendency to invade and destroy nearby tissue and spread to other parts of the body.
melanin (MEL-a-nin): The substance that gives the skin its color.
melanocytes (mel-AN-o-sites): Cells in the skin that produce and contain the pigment called melanin.
melanoma: A form of skin cancer that arises in melanocytes, the cells that produce pigment. Melanoma usually begins in a mole.
metastasize (meh-TAS-ta-size): To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.
nonmelanoma skin cancer: Skin cancer that arises in basal cells or squamous cells but not in melanocytes (pigment-producing cells of the skin).
pathologist (pa-THOL-o-jist): A doctor who identifies diseases by studying cells and tissues under a microscope.
photodynamic therapy (fo-toe-dye-NAM-ik): Treatment with drugs that become active when exposed to light and kill cancer cells.
plastic surgeon: A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases.
precancerous (pre-KAN-ser-us): A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.
prognosis (prog-NO-sis): The likely outcome or course of a disease; the chance of recovery or recurrence.
radiation therapy (ray-dee-AY-shun): The use of high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from material called radioisotopes. Radioisotopes produce radiation and can be placed in or near a tumor or near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance such as a radiolabeled monoclonal antibody that circulates throughout the body. Also called radiotherapy.
recur: To occur again. Recurrence is the return of cancer, at the same site as the original (primary) tumor or in another location, after the tumor had disappeared.
sebum (SEE-bum): An oily substance produced by certain glands in the skin.
skin graft: Skin that is moved from one part of the body to another.
SPF: Sun protection factor, scale for rating the level of sunburn protection in sunscreen products. The higher the SPF, the more sunburn protection it provides. Sunscreens with an SPF value of 2 through 11 provide minimal protection against sunburns. Sunscreens with an SPF of 12 through 29 provide moderate protection, which is adequate for most people. Those with an SPF of 30 or higher provide high protection against sunburn and are sometimes recommended for people who are highly sensitive to the sun.
squamous cell carcinoma (SKWAY-mus. . .kar-sin-O-ma): Cancer that begins in squamous cells, which are thin, flat cells resembling fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.
squamous cells (SKWAY-mus): Flat cells that look like fish scales under a microscope. These cells cover internal and external surfaces of the body.
sunscreen: A substance that helps protect the skin from the sun's harmful rays. Sunscreens reflect, absorb, and scatter both UVA and UVB radiation. Using lotions, creams, or gels that contain sunscreens can help protect the skin from premature aging and damage that may lead to skin cancer.
surgery: A procedure to remove or repair a part of the body or to find out whether disease is present.
topical chemotherapy (kee-mo-THER-a-pee): Treatment with anticancer drugs in a lotion or cream applied to the skin.
tumor (TOO-mer): An abnormal mass of tissue that results from excessive cell division. Tumors perform no useful body function. They may be benign (not cancerous) or malignant (cancerous).
tumor necrosis factor (TOO-mer ne-KRO-sis): A type of biological response modifier (a substance that can improve the body's natural response to disease).
radiation (ul-tra- VYE-o-let
ray-dee-AY-shun): Invisible rays that are part of the energy that comes from
the sun. UV radiation can damage the skin and cause melanoma and other types of
skin cancer. UV radiation that reaches the earth's surface is made up of two
types of rays, called UVA and UVB rays. UVB rays are more likely than UVA rays
to cause sunburn, but UVA rays pass deeper into the skin. Scientists have long
thought that UVB radiation can cause melanoma and other types of skin cancer.
They now think that UVA radiation also may add to skin damage that can lead to
skin cancer and cause premature aging. For this reason, skin specialists
recommend that people use sunscreens that reflect, absorb, or scatter both
kinds of UV radiation.
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