Melanoma

Melanoma: A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

Estimated new cases and deaths from melanoma in the United States in 2009:
 
  New cases: 68,720
 
 
  Deaths: 8,650
 

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.

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.

 Melanomas arising in areas other than the skin (such as intraocular melanoma, which is melanoma arising in the eye) are not discussed here. Also, two more common and less serious types of skin cancer (squamous cell and basal cell cancer).
 

Research continues to teach us more about melanoma. Scientists are learning more about its causes. They are exploring new ways to prevent, find, and treat this disease. Because of research, people with melanoma can look forward to a better quality of life and less chance of dying from this disease.

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.

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 substance that helps keep the skin from drying out. Sweat and sebum reach the skin’s surface through tiny openings called pores.

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 noncancerous 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.

Melanoma

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). Rarely, melanoma may arise in the meninges, the digestive tract, lymph nodes, or other areas where melanocytes are found. Melanomas that begin in areas other than the skin are not discussed in this booklet.

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.

Risk Factors

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:

Dysplastic 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. White people get melanoma far more often than do black people, probably because light skin is more easily damaged by the sun.

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, all family members should be checked regularly by a doctor.

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:

Avoid exposure to the midday sun (from 10 a.m. to 4 p.m.) whenever possible. When your shadow is shorter than you are, remember to protect yourself from the sun.

If you must be outside, wear long sleeves, long pants, and a hat with a wide brim.

Protect yourself from UV radiation that can penetrate light clothing, windshields, and windows.

Protect yourself from UV radiation reflected by sand, water, snow, and ice.

Help protect your skin by using a lotion, cream, or gel that contains sunscreen. Many doctors believe sunscreens may help prevent melanoma, especially sunscreens that reflect, absorb, and/or scatter both types of ultraviolet radiation. These sunscreen products will be labeled with “broad-spectrum coverage.” Sunscreens are rated in strength according to a sun protection factor (SPF). The higher the SPF, the more sunburn protection is provided. Sunscreens with an SPF value of 2 to 11 provide minimal protection against sunburns. Sunscreens with an SPF of 12 to 29 provide moderate protection. Those with an SPF of 30 or higher provide the most protection against sunburn.

Wear sunglasses that have UV-absorbing lenses. The label should specify that the lenses block at least 99 percent of UVA and UVB radiation. Sunglasses can protect both the eyes and the skin around the eyes.
 

People who are concerned about developing melanoma should talk with their doctor about the disease, the symptoms to watch for, and an appropriate schedule for checkups. The doctor’s advice will be based on the person’s personal and family history, medical history, and other risk factors.

 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. Do not use the following pictures to try to diagnose it yourself. Pictures are useful examples, but they cannot take the place of a doctor’s examination.

Thinking of “ABCD” can help you remember what to watch for:

Asymmetry—The shape of one half does not match the other.

Border—The edges are often ragged, notched, blurred, or irregular in outline; the pigment may spread into the surrounding skin.

Color—The color is uneven. Shades of black, brown, and tan may be present. Areas of white, grey, red, pink, or blue also may be seen

Diameter—There is a change in size, usually an increase. Melanomas are usually larger than the eraser of a pencil (1/4 inch or 5 millimeters).

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.

 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. Do not use the following pictures to try to diagnose it yourself. Pictures are useful examples, but they cannot take the place of a doctor’s examination.

Thinking of “ABCD” can help you remember what to watch for:

Asymmetry—The shape of one half does not match the other.

Border—The edges are often ragged, notched, blurred, or irregular in outline; the pigment may spread into the surrounding skin.

Color—The color is uneven. Shades of black, brown, and tan may be present. Areas of white, grey, red, pink, or blue also may be seen.

Diameter—There is a change in size, usually an increase. Melanomas are usually larger than the eraser of a pencil (1/4 inch or 5 millimeters).

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. (The “How To Do a Skin Self-Exam” section has a simple guide on how to do this skin self-exam.) 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) that 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.

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.

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.

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:

Stage 0: In stage 0, the melanoma cells are found only in the outer layer of skin cells and have not invaded deeper tissues.

Stage I: Melanoma in stage I is thin:

The tumor is no more than 1 millimeter (1/25 inch) thick. The outer layer (epidermis) of skin may appear scraped. (This is called an ulceration).

Or, the tumor is between 1 and 2 millimeters (1/12 inch) thick. There is no ulceration.

The melanoma cells have not spread to nearby lymph nodes.

Stage II: The tumor is at least 1 millimeter thick:

The tumor is between 1 and 2 millimeters thick. There is ulceration.

Or, the thickness of the tumor is more than 2 millimeters. There may be ulceration.

The melanoma cells have not spread to nearby lymph nodes.

Stage III: The melanoma cells have spread to nearby tissues:

The melanoma cells have spread to one or more nearby lymph nodes.

Or, the melanoma cells have spread to tissues just outside the original tumor but not to any lymph nodes.

Stage IV: The melanoma cells have spread to other organs, to lymph nodes, or to skin areas far away from the original tumor.

Recurrent: Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may have come back in the original site or in another part of the body.

Treatment

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 are often treated by a team of specialists. The team may include a dermatologist, surgeon, medical oncologist, radiation oncologist, and plastic surgeon.

Surgery

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 the melanoma was not completely removed during the biopsy, the doctor takes out the remaining tumor. In most cases, additional surgery is performed to remove normal-looking tissue around the tumor (called the margin) to make sure all melanoma cells are removed. This is often necessary, even for thin melanomas. If the melanoma is thick, the doctor may need to remove a larger margin of tissue.

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.

Lymph nodes near the tumor may be removed because cancer can spread through the lymphatic system. If the pathologist finds cancer cells in the lymph nodes, it may mean that the disease has also spread to other parts of the body. 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 node(s). (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.

Lymph node dissection—The surgeon removes all the lymph nodes in the area of the melanoma.

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.

Surgery is generally not effective in controlling melanoma that has spread to other parts of the body. In such cases, doctors may use other methods of treatment, such as chemotherapy, biological therapy, radiation therapy, or a combination of these methods

 

 Chemotherapy

Chemotherapy, 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.

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:

Surgery to remove the tumor

Radiation therapy, biological therapy, or chemotherapy to relieve symptoms

Heated chemotherapy drugs injected directly into the tumor

The drugs may be heated before injection. This type of chemotherapy is called hyperthermic perfusion.

 Biological Therapy

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

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.)

Stage 0

People with Stage 0 melanoma may have minor surgery to remove the tumor and some of the surrounding tissue.

Stage I

People with Stage I melanoma may have surgery to remove the tumor. The surgeon may also remove as much as 2 centimeters (3/4 inch) of tissue around the tumor. To cover the wound, the patient may have skin grafting.

Stage II or Stage III

People with Stage II or Stage III melanoma may have surgery to remove the tumor. The surgeon may also remove as much as 3 centimeters (1 1/4 inches) of nearby tissue. Skin grafting may be done to cover the wound. Sometimes the surgeon removes nearby lymph nodes.

Stage IV

People with Stage IV melanoma often receive palliative care. The goal of palliative care is to help the patient feel better—physically and emotionally. This type of treatment is intended to control pain and other symptoms and to relieve the side effects of therapy (such as nausea), rather than to extend life.

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

Radiation therapy, biological therapy, or chemotherapy to relieve symptoms

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:

A new mole (that looks abnormal)

A change in the size, shape, color, or texture of a mole

A sore that does not heal

Check yourself from head to toe. Don’t forget to check all areas of the skin, including the back, the scalp, between the buttocks, and the genital area.

Look at your face, neck, ears, and scalp. You may want to use a comb or a blow dryer to move your hair so that you can see better. You also may want to have a relative or friend check through your hair because this is difficult to do yourself.

Look at the front and back of your body in the mirror, then raise your arms and look at your left and right sides.

Bend your elbows and look carefully at your fingernails, palms, forearms (including the undersides), and upper arms.

Examine the back, front, and sides of your legs. Also look between your buttocks and around your genital area.

Sit and closely examine your feet, including the toenails, the soles, and the spaces between the toes.

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.

Source: NCI (National Cancer Institute)