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Melanoma is the most serious type of cancer of the skin. Each year in the United States, more than 53,600 people learn they have melanoma. Skin cancer is the most frequent cancer in women 25 – 29 years of age, and second most frequent in women 30 – 34 years of age (the first being breast cancer.) Men are more likely to develop skin cancer than are women. In some parts of the world, especially among Western countries, melanoma is becoming more common every year. In the United States, for example, the percentage of people who develop melanoma has more than doubled in the past 30 years. The Skin The skin is the body’s largest organ. It protects against heat, sunlight, injury, and infection. It helps regulate body temperature, stores water and fat, and produces vitamin D. The skin has two main layers: the outer epidermis and the inner dermis. The epidermis is mostly made up of flat, scalelike cells called squamous cells. Round cells called basal cells lie under the squamous cells in the epidermis. The lower part of the epidermis also contains melanocytes. The dermis contains blood vessels, lymph vessels, hair follicles, and glands. Some of these glands produce sweat, which helps regulate body temperature. Other glands produce sebum, an oily 1Adapted from info from the Office on Women’s Health, U.S. Dept. of Health and Human Services, 200 Independence Ave., SW, Room 712E, Washington D.C. 20201 ; Women’s Health Issues: An Overview , May 2001 substance that helps keep the skin from drying out. Sweat and sebum reach the skin’s surface through tiny openings called pores. What Is Melanoma? Melanoma is a type of skin cancer. It begins in cells in the skin called melanocytes. To understand melanoma, it is helpful to know about the skin and about melanocytes—what they do, how they grow, and what happens when they become cancerous. Melanocytes and Moles Melanocytes produce melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes produce more pigment, causing the skin to tan, or darken. Sometimes, clusters of melanocytes and surrounding tissue form non-cancerous growths called moles. (Doctors also call a mole a nevus; the plural is nevi.) Moles are very common. Most people have between 10 and 40 moles. Moles may be pink, tan, brown, or a color that is very close to the person’s normal skin tone. People who have dark skin tend to have dark moles. Moles can be flat or raised. They are usually round or oval and smaller than a pencil eraser. They may be present at birth or may appear later on—usually before age 40. They tend to fade away in older people. When moles are surgically removed, they normally do not return. Understanding Cancer Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body. Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place. Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor. Not all tumors are cancer. Tumors can be benign or malignant:
Cells from malignant tumors can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. That is how cancer cells spread from the original cancer (the primary tumor) to form new tumors in other organs. The spread of cancer is called metasis. Different types of cancer tend to spread to different parts of the body.
Melanoma occurs when melanocytes (pigment cells) become malignant. Most pigment cells are in the skin; when melanoma starts in the skin, the disease is called cutaneous melanoma. Melanoma may also occur in the eye (ocular melanoma or intraocular melanoma). Melanoma is one of the most common cancers. The chance of developing it increases with age, but this disease affects people of all ages. It can occur on any skin surface. In men, melanoma is often found on the trunk (the area between the shoulders and the hips), or the head and neck. In women, it often develops on the lower legs. Melanoma is rare in black people and others with dark skin. When it does develop in dark-skinned people, it tends to occur under the fingernails or toenails, or on the palms or soles. When melanoma spreads, cancer cells may show up in nearby lymph nodes. Groups of lymph nodes are found throughout the body. Lymph nodes trap bacteria, cancer cells, or other harmful substances that may be in the lymphatic system. If the cancer has reached the lymph nodes, it may mean that cancer cells have spread to other parts of the body such as the liver, lungs, or brain. In such cases, the cancer cells in the new tumor are still melanoma cells, and the disease is called metastatic melanoma, not liver, lung, or brain cancer. Melanoma: Who’s at Risk? No one knows the exact causes of melanoma. Doctors can seldom explain why one person gets melanoma and another does not. However, research has shown that people with certain risk factors are more likely than others to develop melanoma. A risk factor is anything that increases a person’s chance of developing a disease. Still, many who do get this disease have no known risk factors. Studies have found the following risk factors for melanoma: Dyplastic nevi: Dysplastic nevi are more likely than ordinary moles to become cancerous. Dysplastic nevi are common, and many people have a few of these abnormal moles. The risk of melanoma is greatest for people who have a large number of dysplastic nevi. The risk is especially high for people with a family history of both dysplastic nevi and melanoma. Many (more than 50) ordinary moles: Having many moles increases the risk of developing melanoma. Fair skin: Melanoma occurs more frequently in people who have fair skin that burns or freckles easily (these people also usually have red or blond hair and blue eyes) than in people with dark skin. Caucasian people get melanoma far more often than do African-American people, probably because the sun more easily damages light skin. Personal history of melanoma or skin cancer: People who have been treated for melanoma have a high risk of a second melanoma. Some people develop more than two melanomas. People who had one or more of the common skin cancers (basal cell carcinoma or squamous cell carcinoma) are at increased risk of melanoma. Family history of melanoma: Melanoma sometimes runs in families. Having two or more close relatives who have had this disease is a risk factor. About 10 percent of all patients with melanoma have a family member with this disease. When melanoma runs in a family, a doctor should check all family members regularly. Weakened immune system: People whose immune system is weakened by certain cancers, by drugs given following organ transplantation, or by HIV are at increased risk of developing melanoma. Severe, blistering sunburns: People who have had at least one severe, blistering sunburn as a child or teenager are at increased risk of melanoma. Because of this, doctors advise that parents protect children’s skin from the sun. Such protection may reduce the risk of melanoma later in life. Sunburns in adulthood are also a risk factor for melanoma. Ultraviolet (UV) radiation: Experts believe that much of the worldwide increase in melanoma is related to an increase in the amount of time people spend in the sun. This disease is also more common in people who live in areas that get large amounts of UV radiation from the sun. In the United States, for example, melanoma is more common in Texas than in Minnesota, where the sun is not as strong. UV radiation from the sun causes premature aging of the skin and skin damage that can lead to melanoma. Artificial sources of UV radiation, such as sunlamps and tanning booths, also can cause skin damage and increase the risk of melanoma. Doctors encourage people to limit their exposure to natural UV radiation and to avoid artificial sources. Doctors recommend that people take steps to help prevent and reduce the risk of melanoma caused by UV radiation:
How To Do a Skin Self-Exam Your doctor or nurse may recommend that you do a regular skin self-exam. If your doctor has taken photos of your skin, comparing your skin to the photos can help you check for changes. The best time to do a skin self-exam is after a shower or bath. You should check your skin in a well-lighted room using a full-length mirror and a hand-held mirror. It’s best to begin by learning where your birthmarks, moles, and blemishes are and what they usually look and feel like. Check for anything new:
By checking your skin regularly, you will become familiar with what is normal for you. It may be helpful to record the dates of your skin exams and to write notes about the way your skin looks. If you find anything unusual, see your doctor right away. Back to Top Signs and Symptoms Often, the first sign of melanoma is a change in the size, shape, color, or feel of an existing mole. Most melanomas have a black or blue-black area. Melanoma also may appear as a new mole. It may be black, abnormal, or “ugly looking.” If you have a question or concern about something on your skin, see your doctor. Thinking of “A-B-C-D” can help you remember what to watch for:
Melanomas can vary greatly in how they look. Many show all of the ABCD features. However, some may show changes or abnormalities in only one or two of the ABCD features. Melanomas in an early stage may be found when an existing mole changes slightly, for example, when a new black area forms. Newly formed fine scales and itching in a mole also are common symptoms of early melanoma. In more advanced melanoma, the texture of the mole may change. For example, it may become hard or lumpy. Melanomas may feel different from regular moles. More advanced tumors may itch, ooze, or bleed. But melanomas usually do not cause pain. A skin examination is often part of a routine checkup by a health care provider. People also can check their own skin for new growths or other changes. Changes in the skin, such as a change in a mole, should be reported to the health care provider right away. The person may be referred to a dermatologist, a doctor who specializes in diseases of the skin. Melanoma can be cured if it is diagnosed and treated when the tumor is thin and has not deeply invaded the skin. However, if a melanoma is not removed at its early stages, cancer cells may grow downward from the skin surface and invade healthy tissue. When a melanoma becomes thick and deep, the disease often spreads to other parts of the body and is difficult to control. People who have had melanoma have a high risk of developing a new melanoma. People at risk for any reason should check their skin regularly and have regular skin exams by a health care provider. Dysplastic Nevi Some people have certain abnormal-looking moles called dysplastic nevi or atypical moles, which are more likely than normal moles to develop into melanoma. Most people with dysplastic nevi have just a few of these abnormal moles; some people have many. People with dysplastic nevi and their health care provider should examine these moles regularly to watch for changes. Dysplastic nevi often look very much like melanoma. Doctors with special training in skin diseases are in the best position to decide whether an abnormal-looking mole should be closely watched or removed and checked for cancer. In some families, many members have a large number of dysplastic nevi, and some have had melanoma. Members of these families have a very high risk of melanoma. Doctors often recommend that they have frequent checkups (every 3 to 6 months) so that any problems can be detected early. The doctor may take pictures of a person’s skin to help show when changes occur. Back to Top Diagnosis If the doctor suspects that a spot on the skin is melanoma, the patient will need to have a biopsy. A biopsy is the only way to make a definite diagnosis. In this procedure, the doctor tries to remove all of the suspicious-looking growth. This is an excisional biopsy. If the growth is too large to be removed entirely, the doctor removes a sample of the tissue. The doctor will never "shave off" or cauterize a growth that might be melanoma. A biopsy can usually be done in the doctor’s office using local anesthesia. A pathologist then examines the tissue under a microscope to check for cancer cells. Sometimes it is helpful for more than one pathologist to check the tissue for cancer cells. Back to Top Staging If the diagnosis is melanoma, the doctor needs to learn the extent, or stage, of the disease before planning treatment. Staging is a careful attempt to learn how thick the tumor is, how deeply the melanoma has invaded the skin, and whether melanoma cells have spread to nearby lymph nodes or other parts of the body. The doctor may remove nearby lymph nodes to check for cancer cells. (Such surgery may be considered part of the treatment because removing cancerous lymph nodes may help control the disease.) The doctor also does a careful physical exam and, if the tumor is thick, may order chest x-rays, blood tests, and scans of the liver, bones, and brain. Stages of Melanoma The following stages are used for melanoma:
The doctor can describe treatment choices and discuss the results expected with each treatment option. The doctor and patient can work together to develop a treatment plan that fits the patient’s needs. Treatment for melanoma depends on the extent of the disease, the patient’s age and general health, and other factors. People with melanoma may have surgery, chemotherapy, biological therapy, or radiation therapy. Patients may have a combination of treatments. Surgery is the usual treatment for melanoma. The surgeon removes the tumor and some normal tissue around it. This procedure reduces the chance that cancer cells will be left in the area. The width and depth of surrounding skin that needs to be removed depends on the thickness of the melanoma and how deeply it has invaded the skin: The doctor may be able to completely remove a very thin melanoma during the biopsy. Further surgery may not be necessary. If a large area of tissue is removed, the surgeon may do a skin graft. For this procedure, the doctor uses skin from another part of the body to replace the skin that was removed. Two procedures are used to remove the lymph nodes: Sentinel lymph node biopsy—The sentinel lymph node biopsy is done after the biopsy of the melanoma but before the wider excision of the tumor. A radioactive substance is injected near the melanoma. The surgeon follows the movement of the substance on a computer screen. The first lymph node(s) to take up the substance is called the sentinel lymph nodes. (The imaging study is called lymphoscintigraphy. The procedure to identify the sentinel node(s) is called sentinel lymph node mapping.) The surgeon removes the sentinel node(s) to check for cancer cells. If a sentinel node contains cancer cells, the surgeon removes the rest of the lymph nodes in the area. However, if a sentinel node does not contain cancer cells, no additional lymph nodes are removed. Therapy may be given after surgery to kill cancer cells that remain in the body. This treatment is called adjuvant therapy. The patient may receive biological therapy. Chemotherapy is the use of drugs to kill cancer cells, is sometimes used to treat melanoma. The drugs are usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Usually a patient has chemotherapy as an outpatient (at the hospital, at the doctor’s office, or at home). However, depending on which drugs are given and the patient’s general health, a short hospital stay may be needed. People with melanoma may receive chemotherapy in one of the following ways: By mouth or injection—Either way, the drugs enter the bloodstream and travel throughout the body. Isolated limb perfusion (also called isolated arterial perfusion)—For melanoma on an arm or leg, chemotherapy drugs are put directly into the bloodstream of that limb. The flow of blood to and from the limb is stopped for a while. This allows most of the drug to reach the tumor directly. Most of the chemotherapy remains in that limb. Biological therapy (also called immunotherapy) is a form of treatment that uses the body’s immune system, either directly or indirectly, to fight cancer or to reduce side effects caused by some cancer treatments. Biological therapy for melanoma uses substances called cytokines. The body normally produces cytokines in small amounts in response to infections and other diseases. Using modern laboratory techniques, scientists can produce cytokines in large amounts. In some cases, biological therapy given after surgery can help prevent melanoma from recurring. For patients with metastatic melanoma or a high risk of recurrence, interferon alpha and interleukin-2 (also called IL-2 or aldesleukin) may be recommended after surgery. Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. A large machine directs radiation at the body. The patient usually has treatment at a hospital or clinic, five days a week for several weeks. Radiation therapy may be used to help control melanoma that has spread to the brain, bones, and other parts of the body. It may shrink the tumor and relieve symptoms. Treatment Choices by Stage The following are brief descriptions of the treatments most often used for each stage. (Other treatments may sometimes be appropriate.)
The patient may have one of the following: Surgery to remove lymph nodes that contain cancer cells or to remove tumors that have spread to other areas of the body Recurrent Melanoma Treatment for recurrent melanoma depends on where the cancer came back, which treatments the patient has already received, and other factors. As with Stage IV melanoma, treatment usually cannot cure melanoma that recurs. Palliative care is often an important part of the treatment plan. Many patients have palliative care to ease their symptoms while they are getting anticancer treatments to slow the progress of the disease. Some receive only palliative care to improve their quality of life by easing pain, nausea, and other symptoms.† The patient may have one of the following:
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