Overview, Causes, & Risk Factors
Melanoma is a type of skin cancer. It is an aggressive skin cancer that can spread to other parts of the body. The incidence of melanoma has been increasing over the last several decades.
Melanocytes are pigment cells that are usually found in the skin. They produce melanin, which is the pigment that gives skin its color. Clusters of melanocytes and surrounding skin sometimes form moles. Moles are benign, or noncancerous, growths. Most people have between 10 to 40 moles on their skin. Moles may be brown, pink, or tan. Moles may be flat or raised and are usually round or oval.
Melanoma, on the other hand, is a cancerous growth. It occurs when pigment cells become malignant, divide without control, and invade the tissue around them. Melanoma is usually found on visible skin but can also occur inside the eye or around the anus. This kind of skin cancer is very aggressive. Cancer cells from the tumor may enter the blood stream. They also may enter the lymphatic system, which has tissues and organs that make and store cells to fight infection. Cancer can spread to another part of the body and form new destructive tumors. This spread of the disease is called metastasis.
Melanoma is strongly related to sun exposure. The incidence of melanoma has increased as people spend more and more recreational time in the sun. A history of blistering sunburns in childhood may significantly raise the risk of melanoma.
Other risk factors that increase a person’s risk for melanoma are:
The peak incidence of melanoma occurs between ages 20 and 45.
It’s important to distinguish between moles and melanoma. The acronym ABCD is an easy way to remember how to distinguish if a suspicious skin lesion needs the attention of a healthcare provider. ABCD stands for:
Any growth on the skin that changes color, becomes larger, has a different shape, or undergoes any other change should be reported. Melanomas usually do not cause pain. However, more advanced tumors may itch, ooze, or bleed. In addition, moles may become lumpy or hard.
If a melanoma is suspected, a biopsy will be done. The entire lesion will be removed along with extra tissue around it. If the growth is too large to remove entirely, a sample will be taken. The lesion must be carefully examined under a microscope to determine if it is a melanoma.
If melanoma is found, additional tests or surgery may be ordered to determine the extent, or stage, of the disease. These tests may include:
Nearby lymph nodes may be removed for examination under a microscope. A new procedure, called sentinel lymph node biopsy, may eventually help to reduce the number of lymph nodes that need to be removed for study. Dye is injected near the tumor area. The lymph node to which the dye flows first is called the sentinel node. The sentinel node or nodes are the areas to which the cancer was likely to spread first. If the sentinel node has no cancer, the remaining lymph nodes may be left in place.
Skin cancer rates are rising. Preventive measures explained below may help to decrease skin cancer risk.
Early detection and treatment of melanoma is also critical. Melanoma can be cured if treated while the tumor is thin and superficial. Advanced, thick, deep tumors are more difficult to control and can spread to other parts of the body. People at higher risk of melanoma may be advised to have checkups more frequently. The healthcare provider may take photos of a person’s skin to help in detecting changes that occur over time.
Melanoma left untreated is fatal. The prognosis for people who receive treatment for melanoma is affected by many factors, including the person’s general condition, response to treatment, and extent of disease. The person’s healthcare provider is in the best position to explain what can be expected in each situation.
Concerns over psychological, emotional, and financial problems are common for those with cancer. Help is available from healthcare providers, social workers, and others for those in need.
Melanoma is not contagious and poses no risk to others.
Complete removal of the melanoma is the first step. The size and depth of the melanoma will indicate the next step. Extra tissue around the tumor is also taken to make sure no cancer is left. If a very large area of skin is removed, a skin graft may be done. Skin is taken from another part of the body to replace the removed skin. Lymph nodes near the tumor will also be removed if it is suspected that the cancer has spread.
Surgery is not effective in curing melanoma that has spread to other parts of the body. Other methods of treatment, such as chemotherapy, biological response modifiers, or radiation therapy might be used in these cases. When these other methods are used after surgery has been done to remove all primary cancerous tissue, the treatment is called adjuvant therapy. Cancer cells that may remain in the body are the targets of adjuvant therapy.
Chemotherapy uses medicines to kill cancer cells. One or more anticancer drugs are given by mouth or by injection into the bloodstream. Medicines used might include dacarbazine, nitrosourea, and cisplatin. These medicines work systemically, or throughout the body.
When the melanoma is located in an extremity, regional perfusion of chemotherapy might be used. The medicine is injected directly into the area that contains the melanoma using a perfusion pump for 1 hour. This technique helps to prevent systemic side effects.
Biological response modifiers, or BRMs, use the body’s immune system to fight cancer or decrease side effects caused by other cancer treatments. Interferon and interleukin-2 may be recommended after surgery for those with metastatic melanoma or a high risk of recurrent disease. Some BRMs such as bacillus Calmette-Guerin (BCG) vaccine and levamisole show promise.
Radiation therapy is used to help relieve symptoms caused by melanoma. It can be used to help control disease that has spread to the brain, bones, and other body parts.
Melanoma that has returned cannot be cured. Therapy is designed to reduce the size of the tumor.
Surgery for melanoma may involve taking a large amount of skin, which will leave a scar. Interferon and other BRMs can cause fatigue and severe flu symptoms. Radiation can cause fatigue and hair loss in the treated area. Chemotherapy side effects are specific to the medicines given. It is helpful to know that side effects eventually go away after treatment stops. Also, the healthcare provider can provide measures to treat or control side effects.
People who have had melanoma are closely followed to make sure the melanoma does not return. The person should also be monitored to make sure no new melanomas occur. If the person has widespread disease, careful follow-up will be necessary to make sure that treatment is effective.
The frequency and type of monitoring will depend on the severity of the disease. A person with advanced melanoma will need more frequent monitoring to assure the best possible supportive care. Frequent skin self-exams will be encouraged. For those with a high risk of recurrence, tests ordered might include X-rays, blood tests, and scans of the chest, bones, brain, and liver. Any new or worsening symptoms should be reported to the healthcare provider.