General Information About Skin Cancer
Stages of Skin Cancer
Treatment Option Overview
Treatment Options for Nonmelanoma Skin Cancer

Basal Cell Carcinoma Squamous Cell Carcinoma

Treatment Options for Actinic Keratosis
To Learn More About Skin Cancer
Get More Information From NCI
Changes to This Summary (10/17/2008)
About PDQ

General Information About Skin Cancer

Key Points for This Section

Skin cancer is a disease in which malignant (cancer) cells form in the tissues of the skin. Skin color and exposure to sunlight can affect the risk of developing nonmelanoma skin cancer and actinic keratosis. Nonmelanoma skin cancer and actinic keratosis often appear as a change in the skin. Tests or procedures that examine the skin are used to detect (find) and diagnose nonmelanoma skin cancer and actinic keratosis. Certain factors affect prognosis (chance of recovery) and treatment options.

Skin cancer is a disease in which malignant (cancer) cells form in the tissues of the skin.

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 3 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: Found in the lower part of the epidermis, these cells make melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes make more pigment, causing the skin to darken.

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Anatomy of the skin, showing the epidermis, dermis, and subcutaneous tissue.

Skin cancer can occur anywhere on the body, but it is most common in skin that has been exposed to sunlight, such as the face, neck, hands, and arms. There are several types of cancer that start in the skin. The most common types are basal cell carcinoma and squamous cell carcinoma, which are nonmelanoma skin cancers. Actinic keratosis is a skin condition that sometimes develops into squamous cell carcinoma.

This summary refers to the treatment of nonmelanoma skin cancer and actinic keratosis. Nonmelanoma skin cancers rarely spread to other parts of the body. Melanoma, the rarest form of skin cancer, is more likely to invade nearby tissues and spread to other parts of the body. See the following PDQ summaries for information on melanoma and other kinds of skin cancer:

• Melanoma Treatment ¹
• Mycosis Fungoides and the Sézary Syndrome Treatment ²
• Kaposi Sarcoma Treatment ³

Skin color and exposure to sunlight can affect the risk of developing nonmelanoma skin cancer and actinic keratosis.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for basal cell carcinoma and squamous cell carcinoma include the following:

• Being exposed to a lot of natural or artificial sunlight.
• Having a fair complexion (blond or red hair, fair skin, green or blue eyes, history of freckling).
• Having scars or burns on the skin.
• Being exposed to arsenic.
• Having chronic skin inflammation or skin ulcers.
• Being treated with radiation.
• Taking immunosuppressive drugs (for example, after an organ transplant).
• Having actinic keratosis.

Risk factors for actinic keratosis include the following:

• Being exposed to a lot of sunlight.
• Having a fair complexion (blond or red hair, fair skin, green or blue eyes, history of freckling).

Nonmelanoma skin cancer and actinic keratosis often appear as a change in the skin.

Not all changes in the skin are a sign of nonmelanoma skin cancer or actinic keratosis, but a doctor should be consulted if changes in the skin are seen.

Possible signs of nonmelanoma skin cancer include the following:

• A sore that does not heal.
• Areas of the skin that are:
  • Small, raised, smooth, shiny, and waxy.
  • Small, raised, and red or reddish-brown.
  • Flat, rough, red or brown, and scaly.
  • Scaly, bleeding, or crusty.
  • Similar to a scar and firm.

Possible signs of actinic keratosis include the following:

• A rough, red, pink, or brown, raised, scaly patch on the skin.
• Cracking or peeling of the lower lip that is not helped by lip balm or petroleum jelly.

Tests or procedures that examine the skin are used to detect (find) and diagnose nonmelanoma skin cancer and actinic keratosis.

The following procedures may be used:

• Skin examination: A doctor or nurse checks the skin for bumps or spots that look abnormal in color, size, shape, or texture.
• Biopsy: All or part of the abnormal-looking growth is cut from the skin and viewed under a microscope by a pathologist to see if cancer cells are present. There are 3 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.

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    Punch biopsy. A hollow, circular scalpel is used to cut into a lesion on the skin. The instrument is turned clockwise and counterclockwise to cut down about 4 millimeters (mm) to the layer of fatty tissue below the dermis. A small sample of tissue is removed to be checked under a microscope. Skin thickness is different on different parts of the body.

  • Excisional biopsy: A scalpel is used to remove the entire growth.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) depends mostly on the stage of the cancer and the type of treatment used to remove the cancer.

Treatment options depend on the following:

• The stage of the cancer (whether it has spread deeper into the skin or to other places in the body).
• The type of cancer.
• The size and location of the tumor.
• The patient’s general health.

Stages of Skin Cancer

Key Points for This Section

After nonmelanoma skin cancer has been diagnosed, tests are done to find out if cancer cells have spread within the skin or to other parts of the body. There are three ways that cancer spreads in the body. The following stages are used for nonmelanoma skin cancer: Stage 0 (Carcinoma in Situ) Stage I Stage II Stage III Stage IV Treatment choices are based on the type of nonmelanoma skin cancer or precancerous skin condition diagnosed: Basal cell carcinoma Squamous cell carcinoma Actinic keratosis

After nonmelanoma skin cancer has been diagnosed, tests are done to find out if cancer cells have spread within the skin or to other parts of the body.

The process used to find out if cancer has spread within the skin or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. A biopsy is often the only test needed to determine the stage of nonmelanoma skin cancer. Lymph nodes may be examined in cases of squamous cell carcinoma to see if cancer has spread to them.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

• Through tissue. Cancer invades the surrounding normal tissue.
• Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
• Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for nonmelanoma skin cancer:

Stage 0 (Carcinoma in Situ)

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Stage 0 nonmelanoma. Abnormal cells are shown in the epidermis (outer layer of the skin).

In stage 0, abnormal cells are found in the squamous cell or basal cell layer of the epidermis (topmost layer of the skin). These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

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Pea, peanut, walnut, and lime show tumor sizes.

Stage I

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Stage I nonmelanoma skin cancer. The tumor is no more than 2 centimeters.

In stage I, cancer has formed and the tumor is 2 centimeters or smaller.

Stage II

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Stage II nonmelanoma skin cancer. The tumor is more than 2 centimeters wide.

In stage II, the tumor is larger than 2 centimeters.

Stage III

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Stage III nonmelanoma skin cancer. The tumor has spread below the skin to nearby tissues and/or lymph nodes.

In stage III, cancer has spread below the skin to cartilage, muscle, or bone and/or to nearby lymph nodes, but not to other parts of the body.

Stage IV

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Stage IV nonmelanoma skin cancer. The tumor has spread to other places in the body, such as the brain or lung.

In stage IV, cancer has spread to other parts of the body.

Treatment choices are based on the type of nonmelanoma skin cancer or precancerous 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 small raised bump that has a smooth, pearly appearance. Another type looks like a scar and is flat and firm to the touch. 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 in 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 burned or exposed to chemicals or radiation. Often this cancer appears as a firm red bump. Sometimes the tumor may feel scaly or bleed or develop a crust. Squamous cell tumors may spread to nearby lymph nodes.

Actinic keratosis

Actinic keratosis is a skin condition that is not cancer, but sometimes changes into squamous cell carcinoma. It usually occurs in areas that have been exposed to the sun, such as the face, the back of the hands, and the lower lip. It appears as rough, red, pink, or brown, raised, scaly patches on the skin, or cracking or peeling of the lower lip that is not helped by lip balm or petroleum jelly.

Treatment Option Overview

Key Points for This Section

There are different types of treatment for patients with nonmelanoma skin cancer and actinic keratosis. Four types of standard treatment are used: Surgery Radiation therapy Chemotherapy Photodynamic therapy New types of treatment are being tested in clinical trials. Biologic therapy Patients may want to think about taking part in a clinical trial. Patients can enter clinical trials before, during, or after starting their cancer treatment. Follow-up tests may be needed.

There are different types of treatment for patients with nonmelanoma skin cancer and actinic keratosis.

Different types of treatment are available for patients with nonmelanoma skin cancer 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.

Four types of standard treatment are used:

Surgery

One or more of the following surgical procedures may be used to treat nonmelanoma skin cancer or actinic keratosis:

• Mohs micrographic surgery: The tumor is cut from the skin in thin layers. During surgery, 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 and is often used to remove skin cancer on the face.
• Simple excision: The tumor is cut from the skin along with some of the normal skin around it.
• Shave excision: The abnormal area is shaved off the surface of the skin with a small blade.
• Electrodesiccation and curettage: 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.
• 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.

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  Cryosurgery. 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.

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. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.

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. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the spinal column, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). Chemotherapy for nonmelanoma skin cancer and actinic keratosis is usually topical (applied to the skin in a cream or lotion). The way the chemotherapy is given depends on the condition being treated.

Retinoids (drugs related to vitamin A) are sometimes used to treat or prevent nonmelanoma skin cancer. The retinoids may be taken by mouth or applied to the skin. The use of retinoids is being studied in clinical trials for treatment of squamous cell carcinoma.

Photodynamic therapy

Photodynamic therapy (PDT) is a cancer treatment that uses a drug and a certain type of laser light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein. 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.

New types of treatment are being tested in clinical trials.

This summary section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied. Information about clinical trials is available from the NCI Web site ⁴.

Biologic therapy

Biologic therapy 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. This type of cancer treatment is also called biotherapy or immunotherapy.

Patients may want to think about taking part in a clinical trial.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's clinical trials database.

Follow-up tests may be needed.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests. This is sometimes called re-staging.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

Treatment Options for Nonmelanoma Skin Cancer

A link to a list of current clinical trials is included for each treatment section. For some types or stages of cancer, there may not be any trials listed. Check with your doctor for clinical trials that are not listed here but may be right for you.

Treatment of basal cell carcinoma may include the following:

• Mohs micrographic surgery.
• Simple excision.
• Electrodesiccation and curettage.
• Cryosurgery.
• Radiation therapy.
• Laser surgery.
• Topical chemotherapy with fluorouracil.
• Photodynamic therapy.
• A clinical trial of biologic therapy.

Follow-up skin exams are important for people with basal cell carcinoma because they are likely to have a new or recurrent tumor within 5 years of the first one. After treatment, the patient should have skin exams every 6 months for 5 years and once a year after that.

Check for U.S. clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with basal cell carcinoma of the skin ⁵.

Treatment of squamous cell carcinoma may include the following:

• Mohs micrographic surgery.
• Simple excision.
• Electrodesiccation and curettage.
• Cryosurgery.
• Radiation therapy.
• Topical chemotherapy with fluorouracil.
• Laser surgery.
• A clinical trial of biologic therapy.
• A clinical trial of biologic therapy and retinoids.

Follow-up skin exams are important for people with squamous cell carcinoma. Because squamous cell carcinoma can spread, patients should have skin exams every 3 months for several years after treatment and then every 6 months.

Check for U.S. clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with squamous cell carcinoma of the skin ⁶.

Treatment Options for Actinic Keratosis

Actinic keratosis is not cancer but is treated because it may develop into cancer. Treatment of actinic keratosis may include the following:

• Topical chemotherapy.
• Cryosurgery.
• Electrodesiccation and curettage.
• Dermabrasion.
• Shave excision.
• Laser surgery.
• Photodynamic therapy.

Check for U.S. clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with actinic keratosis ⁷.

To Learn More About Skin Cancer

For more information from the National Cancer Institute about skin cancer, see the following:

• Skin Cancer Home Page ⁸
• What You Need to Know About™ Skin Cancer ⁹
• Skin Cancer Prevention ¹⁰
• Skin Cancer Screening ¹¹
• Cryosurgery in Cancer Treatment: Questions and Answers ¹²
• Lasers in Cancer Treatment: Questions and Answers ¹³
• Photodynamic Therapy for Cancer: Questions and Answers ¹⁴

For general cancer information and other resources from the National Cancer Institute, see the following:

• What You Need to Know About™ Cancer - An Overview ¹⁵
• Understanding Cancer Series: Cancer ¹⁶
• Staging: Questions and Answers ¹⁷
• Chemotherapy and You: Support for People With Cancer ¹⁸
• Radiation Therapy and You: Support for People With Cancer ¹⁹
• Coping with Cancer ²⁰
• Support and Resources ²¹
• Cancer Library ²²
• Information For Survivors/Caregivers/Advocates ²³

Get More Information From NCI

Call 1-800-4-CANCER

For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 9:00 a.m. to 4:30 p.m. Deaf and hard-of-hearing callers with TTY equipment may call 1-800-332-8615. The call is free and a trained Cancer Information Specialist is available to answer your questions.

Chat online

The NCI's LiveHelp® ²⁴ online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 9:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.

Write to us

For more information from the NCI, please write to this address:

NCI Public Inquiries Office

Suite 3036A

6116 Executive Boulevard, MSC8322

Bethesda, MD 20892-8322

Search the NCI Web site

The NCI Web site ²⁵ provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use our “Best Bets” search box in the upper right hand corner of each Web page. The results that are most closely related to your search term will be listed as Best Bets at the top of the list of search results.

There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.

Find Publications

The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator ²⁶. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237), TTY at 1-800-332-8615.

Changes to This Summary (10/17/2008)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Images were added to this summary.

About PDQ

PDQ is a comprehensive cancer database available on NCI's Web site.

PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. Most of the information contained in PDQ is available online at NCI's Web site ²⁵. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research.

PDQ contains cancer information summaries.

The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries are available in two versions. The health professional versions provide detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions provide current and accurate cancer information.

The PDQ cancer information summaries are developed by cancer experts and reviewed regularly.

Editorial Boards made up of experts in oncology and related specialties are responsible for writing and maintaining the cancer information summaries. The summaries are reviewed regularly and changes are made as new information becomes available. The date on each summary ("Date Last Modified") indicates the time of the most recent change.

PDQ also contains information on clinical trials.

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." 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.

Listings of clinical trials are included in PDQ and are available online at NCI's Web site ²⁷. Descriptions of the trials are available in health professional and patient versions. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Not normal. An abnormal lesion or growth may be cancerous, premalignant (likely to become cancer), or benign.

A precancerous condition of thick, scaly patches of skin. Also called solar keratosis and senile keratosis.

A poisonous chemical used to kill weeds and pests. Also used in cancer therapy.

A small, round cell found in the lower part (or base) of the epidermis, the outer layer of the skin.

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.

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in biological therapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called immunotherapy, biotherapy, biological response modifier therapy, and BRM therapy.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

Primary bone cancer is cancer that forms in cells of the bone. Some types of primary bone cancer are osteosarcoma, Ewing sarcoma, malignant fibrous histiocytoma, and chondrosarcoma. Secondary bone cancer is cancer that spreads to the bone from another part of the body (such as the prostate, breast, or lung).

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The smallest type of blood vessel. A capillary connects an arteriole (small artery) to a venule (small vein) to form a network of blood vessels in almost all parts of the body. The wall of a capillary is thin and leaky, and capillaries are involved in the exchange of fluids and gases between tissues and the blood.

A group of abnormal cells that remain in the tissue in which they first formed. These abnormal cells may become cancer and spread into nearby normal tissue.

A tough, flexible tissue that lines joints and gives structure to the nose, ears, larynx, and other parts of the body.

A flexible tube used to deliver fluids into or withdraw fluids from the body.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A measure of length in the metric system. There are 100 centimeters in a meter and 2½ centimeters in an inch.

Treatment with drugs that kill cancer cells.

A disease or condition that persists or progresses over a long period of time.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called a clinical study.

A procedure in which tissue is frozen to destroy abnormal cells. This is usually done with a special instrument that contains liquid nitrogen or liquid carbon dioxide. Also called cryoablation.

Removal of tissue with a curette (a spoon-shaped instrument with a sharp edge).

A spoon-shaped instrument with a sharp edge.

The lower or inner layer of the two main layers of tissue that make up the skin.

The process of identifying a disease, such as cancer, from its signs and symptoms.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

The drying of tissue by a high-frequency electric current applied with a needle-shaped electrode.

The upper or outer layer of the two main layers of tissue that make up the skin.

Removal by surgery.

A surgical procedure in which an entire lump or suspicious area is removed for diagnosis. The tissue is then examined under a microscope.

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external-beam radiation therapy.

A drug used as a treatment for cancer. It is a type of antimetabolite. Also called 5-FU.

Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

The complex group of organs and cells that defends the body against infections and other diseases.

Describes the ability to decrease the body's immune system responses.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

A type of radiation therapy in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, radiation brachytherapy, and implant radiation therapy.

Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

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.

A surgical procedure that uses the cutting power of a laser beam to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.

An area of abnormal tissue. A lesion may be benign (noncancerous) or malignant (cancerous).

The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.

The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.

A pigment that gives color to skin and eyes and helps protect it from damage by ultraviolet light.

A cell in the skin and eyes that produces and contains the pigment called melanin.

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

A surgical procedure used to treat skin cancer. Individual layers of cancerous tissue are removed and examined under a microscope one at a time until all cancerous tissue has been removed. Also called Mohs micrographic surgery.

The National Cancer Institute, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. The National Cancer Institute conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the National Cancer Institute Web site at http://www.cancer.gov. Also called NCI.

NCI, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. It conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the NCI Web site at http://www.cancer.gov. Also called National Cancer Institute.

Skin cancer that forms in basal cells or squamous cells but not in melanocytes (pigment-producing cells of the skin).

A part of the body that performs a specific function. For example, the heart is an organ.

A doctor who identifies diseases by studying cells and tissues under a microscope.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

Treatment with drugs that become active when exposed to light. These activated drugs may kill cancer cells.

A substance that gives color to tissue. Pigments are responsible for the color of skin, eyes, and hair.

The original tumor.

The likely outcome or course of a disease; the chance of recovery or recurrence.

Removal of a small disk-shaped sample of tissue using a sharp, hollow device. The tissue is then examined under a microscope.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called radiotherapy and irradiation.

Giving off radiation.

A small, radioactive pellet that is placed in or near a tumor. Cancer cells are killed by the energy given off as the radioactive material breaks down and becomes more stable.

To come back or to return.

Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrence.

Treatment with anticancer drugs directed to a specific area of the body.

Vitamin A or a vitamin A-like compound.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

A small, thin knife used for surgery.

A procedure in which a skin abnormality and a thin layer of surrounding skin are removed with a small blade for examination under a microscope. Stitches are not needed with this procedure.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

Cancer that forms in tissues of the skin. There are several types of skin cancer. Skin cancer that forms in melanocytes (skin cells that make pigment) is called melanoma. Skin cancer that forms in basal cells (small, round cells in the base of the outer layer of skin) is called basal cell carcinoma. Skin cancer that forms in squamous cells (flat cells that form the surface of the skin) is called squamous cell carcinoma. Skin cancer that forms in neuroendocrine cells (cells that release hormones in response to signals from the nervous system) is called neuroendocrine carcinoma of the skin. Most skin cancers form in older people on parts of the body exposed to the sun or in people who have weakened immune systems.

The bones, muscles, tendons, and other tissues that reach from the base of the skull to the tailbone. The spinal column encloses the spinal cord and the fluid surrounding the spinal cord. Also called spine, backbone, and vertebral column.

Flat cell that looks like a fish scale under a microscope. These cells cover inside and outside surfaces of the body. They are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body (such as the bladder, kidney, and uterus), and the passages of the respiratory and digestive tracts.

Cancer that begins in squamous cells, which are thin, flat cells that look like 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.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

Abnormal cells are found in the squamous cell or basal cell layer of the epidermis (outer layer of skin). These abnormal cells may become cancer and spread into nearby normal tissue. Also called nonmelanoma carcinoma in situ.

Cancer that forms in squamous cells or basal cells in the skin. The tumor is no more than 2 centimeters.

Cancer that forms in squamous cells or basal cells in the skin. The tumor is more than 2 centimeters.

Cancer that forms in squamous cells or basal cells in the skin. The cancer has spread below the skin to tissues such as cartilage, muscle, or bone and/or to nearby lymph nodes, but not to other parts of the body.

Cancer that forms in squamous cells or basal cells in the skin. The cancer has spread to other places in the body, such as the brain or lung.

Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body. It is important to know the stage of the disease in order to plan the best treatment.

In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with standard therapy. Also called standard of care or best practice.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

Treatment with anticancer drugs that travel through the blood to cells all over the body.

A group or layer of cells that work together to perform a specific function.

Treatment with anticancer drugs in a lotion or cream applied to the skin.

The replacement of tissue with tissue from the person’s own body or from another person.

A surgical tool used to cut out circular pieces of bone or other tissue.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

The formation of a break on the skin or on the surface of an organ. An ulcer forms when the surface cells die and are cast off. Ulcers may be associated with cancer and other diseases.

A blood vessel that carries blood to the heart from tissues and organs in the body.

One of several vitamins that the body needs in small amounts to function and stay healthy. Vitamin A is needed for vision, bone growth, reproduction, growth of epithelium (cells that line the internal and external surfaces of the body), and fighting infections. It is fat-soluble (can be stored in the body’s fatty tissue). Foods with vitamin A include fish oils and liver, egg yolks, and whole milk dairy products from animals. It also can be made in the body from a substance found in fruits and vegetables such as cantaloupes, carrots, spinach, and sweet potatoes. Vitamin A is being studied in the prevention and treatment of some types of cancer. Also called retinol.

A nutrient that helps the body use calcium and phosphorus and make strong bones and teeth. It is found in fatty fish, eggs, and dairy products. The skin can also make vitamin D when exposed to sunshine. Not getting enough vitamin D can cause a bone disease called rickets. Vitamin D is being studied in the prevention and treatment of some types of cancer. Also called cholecalciferol.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.