What Is It?
Melanoma is cancer of the cells that give skin its color (pigment-forming cells). It develops when these cells change and reproduce aggressively. Melanoma, the deadliest form of skin cancer, is the seventh most common cancer in the United States and is increasing at faster rates than any other cancer. Based on cancer patterns between 2000 and 2002, the U.S. National Cancer Institute predicts that 1 in 50 men and 1 in 75 women in the United States will develop melanoma during his or her lifetime. In 1960, only 1 in 600 Americans was expected to develop this cancer.
Why melanoma rates are soaring isn't known. It could be from increased exposure to the sun during recreational activities or possibly from global changes, such as the depletion of the ozone, a gas in the atmosphere that absorbs many harmful solar rays. Your pattern of sun exposure appears to affect your risk of developing melanoma more than the total amount of sun exposure in your lifetime. Short bursts of intense sun appear most dangerous, especially if you get sunburned. Sun exposure can cause changes (mutations) in skin cells' genes, the code within each cell that instructs the cell if, how and when to duplicate itself. Researchers have recently identified several gene mutations shared by many melanoma tumor cells. It is likely that one or more of these gene mutations starts the cancer.
There are four types of melanoma:
Melanoma affects all age groups. Caucasians are 12 times more likely to get melanoma than are African-Americans.
Your risk of developing melanoma is higher if you have:
Features of freckles or moles that raise your risk of melanoma include:
Symptoms
Melanoma is usually visible as a single dark skin spot. It may appear on any skin surface, but most commonly develops on the back, chest and legs. About two-thirds of the time, melanoma develops on normal-looking skin, and one-third of the time, it grows out of an existing mole.
Watch for the A, B, C, D and Es of melanoma:
Also look for bleeding, crusting or numbness in this skin area.
Diagnosis
If your doctor thinks a mole may be melanoma, he or she will either do a biopsy of the skin or refer you to a specialist who does this procedure. In a biopsy, a piece of tissue is removed and examined in a laboratory. A doctor or surgeon usually will remove the entire suspicious area of skin and some surrounding skin as well. A biopsy can estimate how deeply the cancer has invaded, which is the most important factor in predicting the outcome of the disease. Before the biopsy, it is important for your doctor to feel along your skin in areas where lymph nodes normally are to see if any lymph nodes are enlarged. If your biopsy is diagnosed as a melanoma, enlarged lymph nodes are evidence that the cancer has spread. After a skin biopsy, it is possible for nearby lymph nodes to swell because the skin incision is healing.
Determining how far the cancer has spread is the next step. First, the thickness of the tumor is measured. Patients with melanomas deeper than 1 millimeter thick may require a complete physical examination and certain tests to see if the tumor has spread. Such tests may include chest X-rays and computed tomography scans, blood tests and a biopsy of lymph nodes near the melanoma site.
If the cancer is advanced, the biopsy sample of your melanoma may be tested to see if it has one of several gene mutations that are common in melanoma. There are newer treatments for melanoma that have been designed to treat specific genetic subtypes of this cancer.
Expected Duration
Melanoma can usually be cured if it is found and excised early when the tumor is small and has not penetrated deeply into the skin. More advanced melanoma requires prolonged treatment and can be fatal. If you have been diagnosed with one melanoma, you are at risk of developing another, so you should have your skin examined regularly by a health care professional. About 1 out of 20 people who have a melanoma will develop a second melanoma within 20 years.
Prevention
To reduce your risk of melanoma, avoid sun exposure. Severe sunburn is a major risk factor. Childhood sun exposure may present the greatest risk. To be safe in the sun, take the following steps:
Melanoma of the skin is easier than other cancers to find early since it can be seen on your skin. If you are at risk of developing melanoma, ask your doctor to examine your skin. Also ask your doctor how often you should have your skin checked. Your doctor will be especially concerned about watching for skin changes if you have many dyplastic nevi (atypical moles). Because some melanomas can arise from pre-existing moles, your doctor may excise atypical moles, since they may have a higher chance of changing to cancer. In the alternative, your doctor may take photographs to record the appearance of your moles. The doctor then can compare the photos to any future changes in the appearance of the moles.
Examine your own skin regularly, especially if you have risk factors for melanoma. Use a full-length mirror and a hand-held mirror. Have someone examine your scalp using a blow dryer to part your hair. Someone else also can examine your back and other areas that are hard to examine yourself. Watch for new moles and changes in existing moles. Keep an eye on moles that you've had since birth, because these moles may be more likely to turn into melanoma.
Treatment
To treat melanoma a physician must remove the visible tumor along with some normal-looking skin that surrounds the tumor, because this skin can contain microscopic bits of the cancer. The surgeon will try to remove 1 centimeter to 2.5 centimeters of healthy skin around the tumor, depending on the size of the visible melanoma. In some cases, a specialized procedure known as Mohs micrographic surgery may be used to remove the tumor and surrounding area of healthy skin. In this surgery, the tumor is shaved away one thin layer at a time, and each layer is examined under the microscope as it is removed. This technique helps the surgeon to remove the least amount of surrounding skin possible.
If the melanoma is thicker than 1 millimeter, your doctor may want to examine nearby lymph nodes to see if the tumor has spread. One procedure that is commonly used to examine lymph nodes is called sentinel node dissection. Radioactive liquid is injected into the tumor and allowed to flow through the natural drainage pathway that connects the tumor to nearby lymph nodes. The drainage path can be tracked, and the first lymph node in the drainage path is named the sentinel node. The node is removed and examined for cancer cells. When the sentinel node has no cancer, the other nodes are most often cancer-free. If cancer is found in a lymph node, your doctor may recommend additional treatment.
If cancer cells have spread to one or more lymph nodes, some experts recommend that all lymph nodes in the area be removed in a procedure called an elective lymph node dissection. This procedure is controversial. Although spreading cancer cells might be removed, immune cells that are fighting the cancer also are removed. It has not been proven that this procedure makes melanoma patients more likely to survive the disease.
Additional therapies can sometimes help people with tumors that have invaded the skin deeply, people with cancer cells in the lymph nodes and people with cancer that has spread to distant organs (called metastatic disease). Treatment includes chemotherapy, radiation therapy and medicines that boost your immune system's ability to fight the cancer. The most effective medicine that can stimulate your immune system to fight melanoma is interleukin-2, which is given intravenously (into a vein). This drug must be given in high doses, and people who get this treatment need to be in good health for the treatment to be safe.
Other medicines that stimulate the immune system and can treat melanoma are the drug alpha-interferon and various brands of an injected therapy known as the melanoma vaccine. It is not a vaccine that can be used for prevention. The melanoma vaccine is administered after melanoma is diagnosed. It is considered to be a vaccine because it boosts the immune system. The vaccine may help your immune system to build a strong immune reaction against melanoma cells, which could help your body to attack the cancer. Varieties of this vaccine are still being tested.
Genetic changes that are seen in melanoma cells can make these cancer cells more resistant to chemotherapy than other cancers. Several drugs are in development that may help melanoma respond better to chemotherapy medicines.
When To Call a Professional
Early treatment of melanoma is crucial. If you detect any of the ABCDE signs or see any suspicious changes in your skin, contact your doctor right away. If you delay, melanoma can spread. If you have a family history of the disease or other risk factors, be especially alert. Have your doctor examine your skin regularly.
Prognosis
Five key factors help to determine how serious melanoma is:
The thickness of the tumor is the most important factor in predicting whether the illness is treatable. Superficial tumors usually can be cured, but deeper cancers are more difficult, sometimes impossible, to treat. If melanoma cells break away from the tumor and spread through the lymphatic system to organs such as the lungs, liver or brain, the cancer can be cured in only a small percentage of patients.
High-dose interleukin 2 treatment is the first treatment that has been shown to provide a long-term remission or cure of melanoma for some patients. Approximately 10% of people who receive this treatment have a long-term response, but it is possible for the disease to return (relapse) in some of these people.
If treatment begins in the very earliest stages (when the tumor is less than 0.75 millimeters deep), then the chance of cure is excellent. More than 95% of people with small melanomas are cancer-free when they are examined as long as 8 years later. However, for deeper melanomas, the survival rate is poor. Fewer than 50% of people with tumors thicker than 4 millimeters are able to survive for 5 years beyond their diagnosis. If melanoma cells are found within a lymph node, the 5-year survival is between 30% and 50%.
Additional Info
National Cancer Institute (NCI)
U.S. National Institutes of Health
Public Inquiries Office
6116 Executive Blvd.
Room 3036A
Bethesda, MD 20892-8322
Toll-Free: 1-800-422-6237
TTY: 1-800-332-8615
http://www.cancer.gov/
American Cancer Society (ACS)
Toll-Free: 1-800-227-2345
TTY: 1-866-228-4327
http://www.cancer.org/
Cancer Research Institute
National Headquarters
One Exchange Plaza
55 Broadway, Suite 1802
New York, NY 10006
Toll-Free: 1-800-992-2623
http://www.cancerresearch.org/