Melanoma is a type of skin cancer that occurs when melanocytes — the cells that give skin its pigment — are damaged, causing them to grow and divide out of control. Melanoma is far less common than other types of skin cancer, but it is of higher concern because it is much more likely to spread to other parts of the body if not diagnosed and treated early.
While exposure to ultraviolet (UV) radiation from either direct sunlight or tanning beds is the leading cause of melanoma, in rare cases it can be caused by inherited genetic abnormalities. The cause is largely unknown for melanoma that develops in parts of the body that do not receive regular sun exposure, such as under the fingernails and between the toes.
A new mole, a change to an existing mole, or any other change in your skin can be a symptom of melanoma. Healthcare providers recommend paying attention to the presence of any new spot on your skin that appears to be changing in size, shape or color; or a spot on your skin that appears different from the other moles, birthmarks or freckles. Regular skin screenings are also recommended.
- What Is Melanoma?
- Melanoma Symptoms
- Melanoma Causes
- Melanoma Risk Factors
- Melanoma Diagnosis
- Melanoma Stages
- Melanoma Treatment
- Melanoma Survival
- Preventing Melanoma
- Frequently Asked Questions
Melanoma is a type of cancer that affects the skin. It occurs when melanocytes – the cells that give skin its pigment — begin to grow and divide abnormally. There are other more common types of skin cancer, but melanoma is set apart by its concerning ability to spread to other parts of the body. You may also see it referred to as malignant melanoma or cutaneous melanoma.
Rare forms of melanoma can also develop in the eye (uveal melanoma), under the nailbeds (acral melanoma) and in mucous membranes (mucosal melanoma).
A new mole, a change to an existing mole or any other change in your skin can be a symptom of skin cancer. Pay attention to the presence of any new spot on your skin that appears to be changing in size, shape or color. Also watch for any spots on your skin that appear different from other moles, birthmarks or freckles.
The ABCDE Examination
Normal moles are usually the same color or shade throughout, in the shape of a circle or oval, and show a clear border between the mole and the surrounding skin. The ABCDE rule is a common and generally reliable way to evaluate your moles and decide when it’s time to see a doctor.
- “A” is for asymmetry: Does the mole or spot have an irregular shape with two parts that look very different? Or is one half of the mole a mirror image of the other half?
- “B” is for border: Is the border irregular, scalloped or jagged as opposed to smooth?
- “C” is for color: Are there more than 1-2 colors in the mole or is the color distribution uneven? (It is normal for a mole to have a slightly lighter edge and a darker center.)
- “D” is for diameter: Is the mole or spot larger than the size of a pencil eraser?
- “E” is for evolution: Has the mole or spot changed during the past few weeks or months?
Additionally, there are a few other qualities to look for in your moles, including when the surface of a mole changes or appears scaly, bumpy or bleeding; when the darker pigment within a mole spreads into the surrounding skin; and the presence of a new sore that isn’t healing.
It may also help you to examine different images of normal moles versus examples of melanoma to get a better idea of which is which.
Melanoma develops when the DNA in the cells that give your skin its color is damaged, causing these skin cells, or melanocytes, to grow out of control. Exposure to ultraviolet (UV) rays — from the sun or tanning beds — is believed to be the leading cause of skin melanoma. However, UV light is not always the culprit, especially in the case of rare melanomas.
Melanoma can develop in areas of your body that do not receive regular UV exposure, such as the back of the eye (uveal melanoma), under a fingernail or toenail (acral melanoma), between your toes or inside your mouth, esophagus, colon, and genital regions (mucosal melanoma). In some cases, the gene changes that cause melanoma are inherited from a parent.
The most common mutation found in melanoma is in the BRAF gene, which is present in roughly half of all cases. Other genes that often see mutation in melanoma are NRAS, CDKN2A, NF1 and C-KIT. In rare melanomas, BRAF mutations are not as common. GNAQ and GNA11 are found in 90% of uveal melanomas, and CKIT mutations are found at a higher frequency in acral and mucosal melanomas.
There are several known risk factors for developing melanoma:
Having fair skin, light (red or blond) hair and/or freckles put you at greater risk of developing melanoma.
UV Light Exposure
If you frequent tanning beds, have had one or more severe sunburns in your lifetime or are regularly exposed to ultraviolet (UV) light your risk is higher. Also, if you live closer to the equator or at a higher elevation — places where the sun’s rays are more direct — you also stand a greater chance of developing melanoma.
High Number of Moles
If you have a lot of moles on your body you may be at increased risk of melanoma.
If you have atypical moles, you likely have a greater than average chance of developing melanoma. If a condition known as dysplastic nevus syndrome (meaning your body creates abnormal moles) affects you or one of your close relatives, this may also increase your risk.
If someone in your immediate family has been diagnosed with melanoma, you have a greater chance of developing the disease.
Compromised Immune System
If you have a weakened immune system you have an increased risk of developing melanoma and other skin cancers.
How Often Should I Get a Melanoma Screening?
Most experts believe that you should be checked once a year for melanoma. If you are at higher risk for developing the disease, ask your healthcare provider if you should receive more frequent screenings.
Diagnosing melanoma is a relatively straightforward process. Here is a list of what you might experience:
- Physical exam: your doctor will likely start with a physical exam, which usually includes questions about your family medical history, pre-existing conditions and overall health. Your doctor should inspect your skin closely for signs of melanoma and, if any indicators are found, will likely order a biopsy. At the time of the visit, please remove all nail polish for a careful examination of the nail beds.
If melanoma is suspected, you may be referred to a dermatologist (a doctor who specializes in skin diseases).
For melanoma of the eye (uveal melanoma), an annual eye exam is recommended, even if you do not require corrective lenses. More than half of all cases of uveal melanoma are detected during a routine eye exam.
Your dentist and gynecologist also play key roles in performing surveillance for mucosal melanoma.
- Biopsy: to inspect the mole or growth in question, your doctor or dermatologist will remove a piece of it — or in some cases the entire area — and send it to a lab to be examined. There are a variety of biopsy procedures that can be implemented, and most are done using a local anesthetic. Uveal melanomas are rarely biopsied, and the diagnosis is made on the basis of a number of clinical criteria.
I’ve Been Diagnosed with Melanoma, Now What?
If you are diagnosed with melanoma, your doctor will likely recommend follow up testing to determine the thickness, which helps inform the treatment plan and prognosis and to see whether the melanoma has spread to your lymph nodes and other areas of the body.
If you have not yet consulted a dermatologist, now is the time to do so. Find out what stage of the disease you have, what treatment your care team recommends and why.
The staging system that is usually used for skin melanoma is the American Joint Committee on Cancer TNM system, which uses three metrics for classification:
- The depth and extent of the primary tumor (T).
- Whether or not it has spread to nearby lymph nodes (N).
- Whether or not it has metastasized (M) to distant lymph nodes or other organs and tissue.
Using this information, melanoma is categorized between stage 0 (when the disease is confined to the outermost layer of the skin) and stage IV (when the disease has spread to distant parts of the body).
To learn more about melanoma staging, speak with your doctor. They can answer your questions and help you better understand your stage and prognosis.
Melanoma has high rates of survival, especially when found early, and often responds well to treatment. These are the treatment options your doctor may present for skin melanoma:
Surgery is usually the first choice in treatment options for melanoma, and it often results in the disease being cured.
There are several types of surgeries that are commonly used. Wide excision removes the mole or growth in question in addition to a “margin” of healthy skin using just local anesthetic. Mohs Surgery removes the skin in layers until the skin left shows no signs of cancer. In rare cases, this may lead to the amputation of a phalange if it contains many or deep growths.
Immunotherapy helps a patient’s immune system recognize and attack cancer cells, and immune checkpoint inhibitors are one type of immunotherapy used to treat melanoma. While melanoma cells can sometimes “hide” from the immune system, these drugs target specific checkpoints to help facilitate a healthy immune response. Immune checkpoint inhibitors used to treat melanoma include:
- pembrolizumab (Keytruda)
- nivolumab (Opdivo)
- atezolizumab (Tecentriq)
- ipilimumab (Yervoy)
Targeted therapy uses drugs that attack the abnormal proteins created by the mutated genes often found in melanoma cases. These are known as BRAF inhibitors and MEK inhibitors. Targeted therapy drugs used to treat melanoma include:
- vemurafenib (Zelboraf)
- dabrafenib (Tafinlar)
- encorafenib (Braftovi)
- trametinib (Mekinist)
- cobimetinib (Cotellic)
- binimetinib (Mektovi)
Chemotherapy is the use of strong drugs to kill or damage cancer cells. While no longer considered a standard approach for treating melanoma, chemotherapy may be used if the cancer does not respond to other treatment options. When using chemotherapy to treat melanoma, medications can be used both in combination and by themselves. Common chemotherapy drugs for melanoma include dacarbazine and temozolomide.
Here are a few questions to ask when discussing treatment options with your doctor:
- What stage is the cancer and what does that mean?
- Do I need to start treatment right away?
- Which treatment option(s) do you recommend, and why?
- How long will the treatment last?
- What are the risks and side effects?
- How will we know the treatment is working?
Patients with melanoma see very high survival rates overall. According to Surveillance, Epidemiology, and End Results (SEER) data published by the National Cancer Institute, the relative five-year survival rate from 2010 to 2016 was 92.7%, meaning that approximately 93 out of 100 people with melanoma were still alive five years after their diagnosis.
When the disease is localized, the 5-year survival rate is 99%. When melanoma has progressed to be regional, the survival rate is 66.2%, and in the distant phase, 27.3%. Even if you are diagnosed with a later stage of the disease, it is important to recognize that there is hope — regular medical advancements are making progress.
As UV light is by far the largest catalyst of melanoma, finding ways to avoid UV exposure can go a long way in preventing the disease. You can avoid UV exposure by avoiding direct or excessive sunlight, avoiding tanning beds, wearing sunscreen throughout the year and donning protective clothing. Additionally, keeping a close eye on any new or abnormal-looking moles can help you catch the disease early.
The risk factors for uveal, acral, and mucosal melanomas are not clear, therefore there are no clear tips on how to prevent these rare melanomas.
Is Melanoma Hereditary?
While the majority of melanoma cases come from mutations to skin cells from UV light or other acquired causes, the disease can have a genetic cause, although this is less common.
In the case of inherited melanoma, the CDKN2A or CDK4 genes are usually affected. These genes normally help to control cell growth, but mutations can prevent them from functioning properly. BAP1 mutations are also seen in inherited cases of uveal or skin melanoma. These familial cases are thought to represent less than 10% of melanoma diagnoses.