Melanoma
What is Melanoma?
Melanoma is a type of skin cancer most often seen in adults. However, although rare, melanoma affects about 300-400 children and adolescents each year in the United States. Melanomas can develop on any part of the skin. They can also occur in the eye. If left untreated, melanoma can spread to other parts of the body.
In melanoma, cancer forms in skin cells called melanocytes. Melanocytes produce melanin which provides color (pigment) to the skin.
Melanin is a pigment produced by certain skin cells called melanocytes. Melanin helps protect the skin from ultraviolet (UV) radiation from the sun. People with darker skin color have more melanin and are less likely to develop melanoma.
Although usually thought of as an adult disease, melanoma accounts for about 1% of cancers in children under age 15 years. It occurs more often in older age groups, accounting for 7% of cancers in adolescents ages 15-19 years.
Symptoms of melanoma include unusual skin changes such as a mole that grows in size, changes color, bleeds, or itches. Melanomas can also appear as a pale or red colored bump.
Treatment for melanoma depends on the stage of disease. Usually melanoma patients are treated with surgery to remove the cancer. More severe disease may require additional treatment including targeted therapy, chemotherapy and/or immunotherapy.
When caught early, survival rates for melanoma are very good. However, melanoma can spread to lymph nodes and other parts of the body, which can make it hard to treat. For this reason, awareness and early detection of melanoma is very important.
Risk Factors and Causes of Melanoma
Certain factors increase the risk for melanoma. These include having fair skin that burns easily, certain skin conditions, a family history of melanoma and/or unusual moles, and a history of sun exposure or sunburns. Melanoma is more common in adolescents.
- Skin color: People with darker skin are less likely to develop melanoma. People who have fair skin, light or red hair, light colored eyes and tend to sunburn easily are at higher risk.
- Skin conditions: People who are born with large dark spots on their skin called melanocytic nevi are more likely to develop melanoma. Certain inherited conditions such as xeroderma pigmentosum, retinoblastoma, and Werner syndrome can also increase risk.
- Family history: Having a family history of melanoma or unusual moles increases a person’s risk of melanoma.
- UV light exposure: Ultraviolet (UV) radiation damages the DNA of skin cells. Sunlight is the main source of UV exposure. Tanning beds are another source of UV radiation. Exposure to sun and use of tanning beds is a significant risk factor for melanoma.
- Sunburns: People with a history of blistering sunburns are more likely to develop melanoma.
- Radiation therapy and prior cancer: Patients treated with radiation therapy have a higher risk of developing future melanoma.
- Weakened immune system: Low immunity due to serious illness or transplant can increase risk for melanoma.
Signs and Symptoms of Melanoma
Signs of melanoma include changes to the skin including:
- A mole or bump on the skin that grows in size or changes shape, especially if changes occur in a short period of time
- An irregular shaped mole or one that is large in size
- A pale or red colored bump on the skin
- A mole or bump that itches or bleeds
A helpful way to think about signs of melanoma is to remember the ABC’s:
A: Asymmetry
B: Border irregularity
C: Color variation
D: Diameter (> 5 millimeters)
E: Evolution or Evidence of change
Diagnosis of Melanoma
Several types of procedures and tests are used to diagnose melanoma. These include:
- A health history and physical exam to learn about symptoms, general health, past illnesses, family history, and other risk factors.
- Skin exam to check for moles, bumps, and areas of the skin that look unusual.
- A biopsy of the skin tissue to make a diagnosis of melanoma. The cells are then examined with a microscope to look for signs of cancer. In a biopsy for melanoma, it is important to collect tissue from deeper levels of the skin to see how far the tumor extends from the surface. This procedure should be performed by a dermatologist with specific training and expertise in evaluating possible melanoma.
If doctors are concerned that melanoma may have spread, additional tests may be needed. These include:
- Blood tests including level of lactate dehydrogenase (LDH), a substance in the blood that may be elevated in melanoma.
- Lymph node mapping and biopsy to examine spread of melanoma to nearby lymph nodes. In this procedure, called sentinel lymph node biopsy, a special dye or radioactive substance is injected near the site of melanoma. The dye travels through the lymphatic system to the first lymph nodes near the original tumor. Those lymph nodes can be removed and evaluated for signs of cancer. This is important to determine stage of melanoma and help plan treatments.
- Imaging tests are used to identify spread of melanoma to other parts of the body. Tests are done in selected cases depending on the characteristics of the tumor and the involvement of lymph nodes. Some of the imaging tests may include MRI, PET scan, or CT.
- Magnetic resonance imaging (MRI) makes detailed pictures of the body using radio waves and magnets.
- Positron emission tomography (PET) Scan uses radioactive glucose (sugar) given through a vein to make computerized images of the body. The glucose travels through the body and is taken up by cells which use sugar for energy. This allows the different tissues and organs to appear as colored pictures on a computer screen. Cancer cells often grow and divide faster than other cells, and they take up more glucose. PET can sometimes detect cancer in areas of the body that do not appear on a CT scan or MRI.
- Computed tomography (CT or CAT Scan) uses X-rays to create images of the organs and tissues inside the body.
PET scan showing metastatic melanoma in a pediatric patient. Green arrows mark where cancer has spread.
There are several subtypes of melanoma:
- Nodular melanoma – aspects of the tumor grow more deeply into the skin
- Superficial Spreading melanoma – tends to be more flat and broad
- Lentigo maligna melanoma
- Acral lentigious melanoma – occur on places like the soles of the feet
- Spitzoid melanoma (spitz nevus melanoma)
Spitzoid melanoma is the most common type of melanoma that is seen in younger patients.
Staging of Melanoma
Melanoma is classified as Stage I or II (melanoma in skin only), Stage III (melanoma has spread to lymph nodes), or Stage IV (metastatic melanoma).
Factors that determine melanoma stage include:
- Tumor thickness or how deep melanoma is found in the skin
- If the tumor has cracked or broken through top layer of the skin (ulcerated)
- Whether the tumor has spread to lymph nodes
- Whether the tumor has spread to other parts of the body
| Stage | Description |
|---|---|
| Stage 0 |
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| Stage IA |
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| Stage IB |
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| Stage IIA |
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| Stage IIB |
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| Stage IIC |
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| Stage III |
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| Stage IV |
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Prognosis for Melanoma
The chance of recovery from melanoma depends on a variety of factors such as:
- Thickness of the tumor
- Location of the tumor
- Whether the cancer has spread to lymph nodes or other parts of the body (metastatic) and the number of metastatic sites
- The ability of surgery to completely remove the tumor
- Level of lactate dehydrogenase (LDH) in the blood
Overall, the stage of disease is the most important factor for prognosis. Patients with localized melanoma that has not spread have an excellent prognosis with survival rates greater than 90%. However, patients with distant spread of disease are more difficult to treat.
Treatment of Melanoma
Treatment for melanoma depends on the location of the melanoma, features of the tumor (gene changes and histology), and stage of disease.
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Surgery is the main treatment for melanoma. Melanoma may penetrate multiple layers of the skin. In order to remove all of the cancer, a large area of skin may be removed around the melanoma. A skin graft may be needed to close the wound. Lymph node biopsy and removal of lymph nodes (dissection) may also be needed. Patients with localized tumors (Stage I and II) that have not spread may be treated with surgery alone.
If melanoma has spread to lymph nodes or other parts of the body, additional treatments are needed including, immunotherapy and/or chemotherapy.
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Immunotherapy uses the body’s own immune system to kill cancer cells. A variety of immunotherapy agents are being studied in melanoma. Some of the medicines act to block the signals that control the growth of cancer cells. Other agents use special proteins that attach to cancer cells so that immune cells are then able recognize and kill the cancer.
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Targeted therapies are drugs that work by acting on, or targeting, specific features of tumor cells such as genes and proteins. Some melanoma patients have a change or mutation in the BRAF gene. This causes cells to make an abnormal protein. Drugs that block the abnormal BRAF protein include BRAF inhibitors (vemurafenib, dabrafenib) and MEK protein inhibitors (trametinib, cobimetinib). About half of melanomas involve a BRAF mutation, and targeted therapy may be helpful for these patients.
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Chemotherapy (“chemo”) may be used to treat metastatic melanoma. However, melanoma does not always respond to chemotherapy. Depending on the location of the tumor and stage of disease, chemotherapy may be systemic or regional. Systemic chemotherapy works throughout the body. It may be given by injection or taken by mouth. Regional chemotherapy works mainly on cancer cells in one area of the body.
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Radiation therapy may be used to treat melanoma that has spread to lymph nodes or other parts of the body like the brain.
Children may be offered treatment for melanoma as part of a clinical trial.
Life after Melanoma
Prevention of melanoma
Survivors of melanoma are at higher risk for recurrence. Melanoma survivors should have regular exams by a dermatologist at least every 6 months. Survivors should check their skin regularly and see a doctor at any sign of change. Here are some simple ways to help prevent melanoma:
- Limit sun exposure.
- Wear sunscreen.
- Avoid tanning beds.
- Know your skin.
- Check medicines for increased sun sensitivity.
View the Kid’s Guide to Self-Screening from the Melanoma Research Foundation.
Do you know how to slip, slop, slap? Find out more about sun safety:
Late effects of treatment
For general health and disease prevention, all cancer survivors should adopt healthy lifestyle and eating habits, as well as continue to have regular physical checkups and screenings by a primary physician at least yearly.
Childhood cancer survivors treated with chemotherapy or radiation should be monitored for acute and late effects of therapy.
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Reviewed: June 2018