The three major forms of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. (The term "carcinoma" refers to cancer that begins in the cells that line or cover an organ.) Melanoma, which means "black tumor," is a skin cancer that begins in cells called melanocytes. These cells produce the dark, protective pigment called melanin. It is melanin that gives skin its color. Although most melanomas are found on the skin, about 10% of melanomas affect the eye. This document focuses on skin melanomas.
Melanoma is the most dangerous type of skin cancer. Because melanocytes are involved, most melanomas are black or brown in color. However, if the cancerous cells stop producing pigment, a melanoma may be skin-colored, pink, red, or purple.
Melanoma can affect any area of the body. Men are more prone to melanoma on the trunk whereas women are more likely to have melanoma develop on the arms and legs.
About 30% of melanomas begin in existing moles (darkened spots on the skin). Skin melanoma grows quickly and has the ability to spread to any organ. Early detection is especially important with melanoma, because treatment success is directly related to the size and depth of the cancerous growth. Some melanomas grow outward on the surface of the skin and some spread vertically into the deep skin layers.
What are the signs of melanoma?
The most common warning sign of skin cancer is a change in the skin, especially a new growth or a sore that doesn’t heal. Some skin cancers can appear as moles, scaly patches, open sores, or raised bumps. Tell your doctor about any sores that won’t go away, unusual bumps or rashes, or changes in your skin or in any existing moles.
The American Academy of Dermatology’s "ABCDE" is a useful and easy-to-remember mnemonic for early melanoma detection. It reflects the appearance of moles on your skin and can be an early warning of melanoma. ABCDE stands for:
- Asymmetry — The shape of one half of the mole does not match the other half.
- Border — The border, or edges, of the mole are ragged, notched, or blurred.
- Color — The color of the mole is mottled and uneven, with shades of brown, black, gray, red, and white.
- Diameter — The size of the mole is usually large, greater than the tip of a pencil eraser (6.0mm).
- Elevation — The mole is raised off of the skin. Elevation is almost always present, but the mole may also be flat.
- Enlargement — A mole that has increased in size is one the most important signs.
- Evolution--- A mole that changes in appearance in a short period of time.
Some melanomas do not fit the ABCDE rule, so it is very important to be aware of any changes in the mole or any area of your skin.
What causes melanoma?
Most experts agree that the main cause of skin cancer is overexposure to sunlight, especially when it results in sunburn and blistering. Researchers believe that ultraviolet (UV) rays from the sun damage the skin and, over time, lead to skin cancer. Repeated exposure to X-rays and certain chemicals, as well as a family history of skin cancer, also can increase the risk of developing the disease.
Although anyone can develop melanoma, the following groups of people have an increased risk for developing the disease:
- Personal history (have had melanoma before)
- People with light skin
- People with blond or red hair
- People with blue eyes
- People with a history of prolonged or excessive sun exposure, including blistering sunburns, in youth
Although malignant melanoma is more common in Caucasians, melanoma can occur in people of all skin types. A family history of melanoma or "atypical" moles is an added risk factor, as is the presence of many moles. However, some people at risk may not have any moles; for example, people with red hair or freckles.
How common is melanoma?
Skin cancer is the most common form of cancer in the United States. In fact, half of all new cancers are skin cancers. An estimated 1 million Americans are diagnosed with skin cancer each year.
Melanoma affects about 50,000 Americans each year. It accounts for more than 80% of skin cancer-related deaths and 1% to 2% of all cancer deaths in the United States. Melanoma usually occurs in adults, but it occasionally is found in children and adolescents. It is the most common cancer in women ages 25 to 29, and the second most common cancer in women ages 30 to 34, as well as in men ages 30 to 49.
How is melanoma diagnosed?
If you have a mole or other spot on your skin that is causing you concern, show it to your health care provider. He or she will check your skin carefully. If the mole or spot doesn’t look normal, the doctor will remove it and look at it under the microscope to see if it contains cancer cells. This is called a biopsy.
Melanomas are grouped by the size of the tumor and how far it has spread. The depth of the melanoma is the most important factor that influences prognosis. This information is used when planning treatment.
Melanomas are also grouped into stages:
- Stage IA — The melanoma is in one area and is 0.75 mm or smaller, or level 2.
- Stage IB — The melanoma is in one area and is 0.76 mm to 1.5 mm in size or level 3.
- Stage IIA — The melanoma is in one area and is greater than1.6 mm to 4 mm in size or level 4.
- Stage IIB — The melanoma is in one area and is greater than 4 mm in size or level 5.
- Stage III — The melanoma has spread to nearby lymph nodes or has begun attacking nearby organs. (Lymph nodes are small, bean-shaped structures found throughout the body that produce and store infection-fighting cells.)
- Stage IV — The melanoma affecting nearby organs is advanced or the cancer has spread to distant organs.
In addition to local excision, tests that may help in staging include a biopsy of sentinel lymph nodes (sentinel lymph nodes are the lymph nodes to which cancer cells are most likely to spread), a chest X-ray, a computed tomography (CT) scan, a magnetic resonance imaging (MRI) scan, and a positron emission tomography (PET) scan.
How is melanoma treated?
The goal of treatment for skin cancer is to remove or destroy the cancer, while saving as much healthy skin as possible. Treatment of melanoma depends on the stage of the cancer.
Surgery is the primary treatment for all stages of melanoma. Surgery involves cutting out the cancer and some of the normal skin surrounding it. The doctor may take out the melanoma using one of the following operations:
- Conservative re-excision is an operation to take out any cancer that remains following biopsy, along with a small border of normal-appearing skin around it (usually less than one-half inch).
- Wide surgical excision takes out the cancer and a margin of healthy skin around the tumor. The amount of healthy skin removed will depend on the size of the skin cancer.
If the tumor is large, a skin graft may be required to close the wound. To do this, the doctor takes a piece of healthy skin from another part of the body to replace the section of skin that was removed. Some of the lymph nodes around the area may be removed if the physician suspects that the cancer has spread.
The following treatments may be used in the later stages of melanoma, when it has begun spreading to lymph nodes and organs:
Chemotherapy — This is the use of drugs to kill cancer cells. If the doctor removes all the cancer that can be seen at the time of the operation, a patient may be given chemotherapy after surgery to kill any cancer cells that are left. Chemotherapy given after an operation to a person who has no cancer cells that can be found is called adjuvant chemotherapy. Adjuvant therapy has been shown to be effective for patients whose disease has spread to their lymph nodes. Chemotherapy alone has not been shown to be effective in treating melanoma.
If the melanoma occurs on an arm or leg, chemotherapy may be given with a technique called isolated arterial perfusion. In this method, chemotherapy drugs are infused directly into the bloodstream of the arm or leg in which the melanoma is found, while blood flow is temporarily stopped. This technique allows most of the drug to reach the tumor directly.
Radiation therapy — Radiation therapy uses X-rays or other high-energy rays to kill cancer cells and shrink tumors. It can be used to help shrink large tumors and relieve symptoms.
Biological therapy — Biological therapy uses the immune system, the body’s natural defense against infection and disease, to fight cancer. Biological treatment is sometimes called biological response modifier therapy or immunotherapy.
Some patients with skin cancer may participate in a clinical trial. A clinical trial is a research program conducted with patients to evaluate a new medical treatment, drug or device. Clinical trials are being done to find new adjuvant chemotherapy drugs and biological therapies that are effective against melanoma.
What is the outlook for people with melanoma?
Nearly all skin cancers can be cured if they treated before they have a chance to spread. When they are not treated, skin cancer can be deadly. The earlier skin cancer is found and removed, the better your chances for a full recovery.
Can melanoma be prevented?
Prevention and early detection are the best ways to reduce the risks associated with skin cancer. Prevention means guarding your skin from the known risk factors for skin cancer. Prevention includes protecting yourself from excess sun and sunburns. Ways to reduce your risk include:
- Do not spend long periods of time in direct sunlight. Avoid the sun between 11 a.m. and 2:30 p.m. In addition, avoid exposure to artificial forms of UV radiation, such as sunlamps and tanning beds.
- Wear hats with brims to protect your face and ears, and sunglasses to protect your eyes. When possible, wear long-sleeved shirts and pants to protect your arms and legs.
- Use a broad-spectrum sunscreen with a skin protection factor (SPF) of 15 or higher. Apply the lotion 30 minutes before you go outside and re-apply it every 2 hours. (Broad-spectrum sunscreens protect against UV-B and UV-A rays.) Also, use a lip balm with sunscreen. Don’t forget to apply sunscreen to young children and to infants older than 6 months.
Early detection involves regularly inspecting your body for any changes in your skin. Be sure to tell your doctor about any new or changing moles, sores, or discolorations. In addition, have your doctor routinely perform a total skin examination to look for signs of skin cancer.
When should I call my doctor?
You should have a skin examination by a doctor if you have any of the following:
- Family history of skin cancer
- Skin that doesn’t tan easily and a history of intense or prolonged sun exposure
- Any pigmented mole that was present at birth
- Any new moles appearing after puberty
- Many (uncountable) moles or any large moles
- A mole that is changing in size, color, or shape
- Any mole that itches or is tender for more than two weeks
- Any mole considered "ugly" because of its size, color, or shape
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 5/7/2009…#14391