What Is It?
In melanoma, cells that give skin its color (pigment-forming cells) undergo cancerous changes and reproduce aggressively to form a life-threatening tumor. 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. Current estimates predict that one in 75 Americans will develop melanoma during his or her lifetime. In 1960, only one 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. A person’s pattern of sun exposure appears to contribute more to the risk of developing melanoma than the total amount of lifetime sun exposure. 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. Recently, researchers identified a gene mutation that is shared by the majority of melanoma tumor cells. It is probably this gene mutation that starts the cancer.
There are four types of melanoma:
- Superficial-spreading melanoma — This is the most common type, and it can cause tumors on any part of the body. As its name suggests, this cancer spreads on the surface of the skin before it invades deeper tissues.
- Nodular melanomas — This type of melanoma invades the deeper tissues, making it a more dangerous form of melanoma.
- Acral lentiginous melanoma — This type of melanoma is found most commonly in dark-skinned people, usually on the palms, soles and nail beds. This is the most serious form of melanoma.
- Lentigo maligna melanoma — This is the slowest growing form of melanoma. It usually occurs in elderly patients on sun-damaged skin (usually the head or neck). A precancerous skin spot called lentigo maligna sometimes develops before the cancer.
Melanoma affects all age groups. Caucasians are 12 times more likely to get this type of cancer than are African-Americans.
Your risk of developing melanoma is higher if you have:
- Red or blond hair, or green or blue eyes
- Fair skin
- Excessive sun exposure, especially in childhood
- A first-degree relative (mother, father, sister or brother) with melanoma — If you have a first-degree relative with melanoma, you are eight times more likely to develop melanoma.
The following skin changes indicate an increased risk of melanoma:
- New mole appearing after age 30
- New mole at any age if it is in an area that is rarely exposed to the sun
- Change in existing mole
- One or more dysplastic nevi, also called “atypical moles” — A mole is given this distinction if it has any features that make it resemble a melanoma. A dysplastic nevus frequently includes both a raised and a flat area of pigmented skin, giving it the appearance of a fried egg.)
- At least 20 moles greater than 2 millimeters in diameter
- At least five moles greater than 5 millimeters in diameter (larger than a pencil eraser)
- Freckles caused by exposure to the sun
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 arises on previously normal-looking skin, and one-third of the time, it grows out of an existing mole. The appearance of a new mole or a change in an existing mole is a worrisome sign.
Watch for the A, B, C, D and Es of melanoma:
- Border irregularities
- Color variation (different colors within the same mole)
- Diameter greater than 6 millimeters (larger than a pencil eraser)
Also look for bleeding, crusting or a change in sensation (the feeling of touch in the area).
If your doctor thinks a worrisome-looking mole may be melanoma, he or she will either biopsy 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. Lymph nodes should be examined before the biopsy, to see if there is evidence that the melanoma 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. If the melanoma is less than 1 millimeter thick, further testing is not necessary. Patients with deeper cancers may require a complete physical examination to see if the tumor has spread. Your doctor may order blood tests, chest X-rays and Computed tomography (CT) scans to check for tumors.
Melanoma can be cured if it is found and treated 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 one out of 20 people who have a melanoma will develop a second melanoma within 20 years.
To prevent 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:
- Apply generous amounts of sunscreen with a sun-protection factor (SPF) of at least 15.
- Wear protective sunglasses, clothing (long sleeves and long pants) and broad-brimmed hats.
- Avoid the peak hours of sun intensity (10 a.m. to 4 p.m.).
- Ask your doctor if your medications increase your sensitivity to the sun, because many medications make your skin more vulnerable to sun damage.
- Avoid tanning salons. If you want to appear tan, use commercial sunless tanning creams. Many varieties are available in department and drug stores.
Unlike internal cancers, melanoma is visible on your skin, making early detection easier. If you are at risk of developing melanoma, ask your doctor to perform a complete skin evaluation. Also ask your doctor how often you should have your skin checked. If you have worrisome-looking moles, your doctor may take photographs to record their appearance. 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 (use a blow-dryer to part your hair), 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 have a greater chance of turning into melanoma.
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 extensions 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 Moh’s 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. With this technique, the exact dimension of the melanoma can be determined, which 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 almost always also 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 lymph-node dissection makes melanoma patients more likely to survive the disease.
Patients with tumors that have invaded the skin deeply or cancer cells in the lymph nodes can be aided by additional therapies that stimulate the body’s immune system to fight melanoma. They include the drug alpha-interferon and an injected therapy known as the melanoma vaccine (Oncophage or Melacine) that is in the final stages of testing after receiving “fast track” consideration by the U.S. Food and Drug Administration. This treatment is considered to be a vaccine because it boosts the immune system. Some scientists have proposed a new category for this drug that would distinguish it from vaccines that are used for prevention. They are proposing that it be called a theracine instead of a vaccine. The melanoma vaccine is administered after melanoma has become established to prevent it from spreading and help your body to attack the cancer.
Cancer that has spread to distant organs (called metastatic disease) is incurable, but treatment with chemotherapy, radiation therapy or alpha-interferon may improve symptoms and prolong life.
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.
Five key factors help to determine how serious melanoma is:
- Tumor thickness (depth into the skin)
- Location — Melanoma on the arms or legs is not as serious as melanoma somewhere else on the body.
- Age — People older than 60 are in more danger.
- Gender — Males are more likely to die of the disease.
- Spread of the tumor beyond the skin — Twenty percent of people with melanoma have cancer in lymph nodes at the time of their diagnosis.
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’t be cured.
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 percent of people with small melanomas are cancer-free when they are examined as long as eight years later. However, for deeper melanomas, the survival is poor. Fewer than 50 percent of people with tumors thicker than 4 millimeters are able to survive for five years beyond their diagnosis. If melanoma cells are found within a lymph node, the five-year survival is between 30 percent and 50 percent.
Diseases and Conditions Center
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.