Understanding Melanoma: Causes, Symptoms and Treatments
Medically Reviewed by Kelsey Powell, MS, Medical Sciences
Understanding Melanoma: Causes, Symptoms and Treatments
Melanoma is a type of skin cancer that develops in the skin cells (melanocytes) responsible for producing the pigment that gives your skin color (melanin). It’s usually caused by ultraviolet (UV) rays from the sun or tanning beds. With melanoma, melanocytes that have mutated — meaning they’ve undergone spontaneous changes that can make them harmful — multiply quickly. This rapid growth forms tumors in the epidermis, your skin's top layer, and the diseased cells can spread to other parts of your body without effective treatment.
Melanoma rates have been rising over the past few decades. According to the American Cancer Society, approximately 106,000 new cases are diagnosed each year in the United States alone. Melanoma is more prevalent in fair-skinned individuals, and white people are more than 20 times more likely to develop the disease than Black people. Melanoma is also more common in men. However, other factors can also influence an individual’s risk of developing the disease.
Melanoma isn’t the most common type of skin cancer; however, it does have the highest death and metastasis (meaning it’s moved to different areas of your body) rates. There are four main types of melanoma:
- Superficial spreading melanoma is the most common type that accounts for approximately 70% of all cases. It usually begins as a pre-existing mole.
- Nodular melanoma is the second most common type that accounts for approximately 15–30% of cases. It’s a more aggressive form that tends to develop faster.
- Lentigo maligna melanoma accounts for approximately 4–10% of cases. It typically appears as large, flat skin lesions and has a lower risk of spreading.
- Acral lentiginous melanoma accounts for approximately 2–8% of cases in fair-skinned individuals and up to 60% of cases in darker-skinned individuals. It’s usually present on the palms, on the feet or under the nail beds, and the lesions are very large in diameter.
Other rarer forms of melanoma include mucosal and ocular melanoma. Mucosal melanoma occurs in the mucosal tissue of body cavities or organs. Common sites include the head and neck and the gastrointestinal and genital regions. Ocular melanoma affects cells in the eyes and can occur in different parts of the eye.
Early diagnosis and treatment lead to a high cure rate for melanoma in most cases. If you delay treatment, however, melanoma may spread to other parts of your body, making it difficult to treat successfully. Melanoma is responsible for the most deaths out of all skin cancers.
Symptoms of Melanoma
Melanoma does present with some warning signs. Moles and brown spots on the skin are common and usually benign, or harmless. However, they can also be symptoms of melanoma. Melanoma can develop anywhere on skin, but it most frequently appears on the trunk areas of fair-skinned men and the legs of fair-skinned women. On darker-skinned individuals, melanoma most commonly develops on the palms, on the soles of the feet or under the nails.
One of the first symptoms of melanoma is the appearance of atypical moles. These moles are often asymmetrical in shape and different in color. Sometimes a malignant, or cancerous, mole will have a variety of shades of brown, black or tan running through it. Cancerous moles may also have blue, red or white coloration. Atypical moles often have irregular borders, sometimes appearing notched or scalloped.
The size of a mole is also important. Benign moles are usually smaller, whereas malignant moles are usually larger than a quarter-inch in diameter. Another characteristic of a malignant mole is its evolution, meaning it’ll change in appearance over time.
An easy way to help identify atypical moles that may be early signs of melanoma is by learning the ABCDEFs of skin cancer:
- Asymmetry: Check for moles with an asymmetrical or irregular shape (is one half of the mole different from the other?).
- Border: Check for moles with irregular, notched or scalloped borders.
- Color: Check for moles with color variations or moles that have darkened in color.
- Diameter: Check for moles that are larger than a quarter-inch in diameter (about the size of a pencil eraser).
- Evolution: Check moles for changes in appearance over time.
- Feeling: Check for any changes in sensation on or around moles (such as pain or itchiness).
Causes of and Risk Factors for Melanoma
Generally, exposure to UV radiation from the sun or tanning beds causes melanoma. UV rays damage the DNA of skin cells and cause them to grow irregularly. However, it’s important to note that you can still develop melanoma on body parts that don't get as much direct sunlight, like the palms of your hands and retinas in your eyes.
Various risk factors contribute to your chance of developing melanoma, including genetics. According to the American Cancer Society, nearly 10% of individuals who develop melanoma have a family history of the disease. Fair or light skin and numerous irregular moles are other risk factors that could make you more susceptible to developing this type of skin cancer.
Additionally, there’s a higher risk of melanoma in people who have suppressed immune systems, and the risk of metastatic melanoma increases when visible primary melanomas haven’t been removed. This type of cancer becomes more common with age, but it occurs in younger people as well.
Melanoma has several stages, which are used to classify the cancer’s degree of severity. The stage is based on the depth of penetration, the degree of spreading and the thickness of the tumor:
- Stages 0 and I are early stages. In stage 0, the growths are localized and noninvasive. Stage I involves invasion into the dermis level, but the tumors are small.
- Stage II tumors are larger and may show additional characteristics, such as ulceration, which means there’s a break or crack in the skin. This stage is considered an intermediate risk.
- Stage III melanoma exhibits ulceration, which indicates significant progression. At this stage the cancer can affect lymph nodes, which can carry cancer to other organs.
- Stage IV melanoma is the most advanced stage and involves metastasis to the lymph nodes and internal organs, such as the lungs, liver, brain, bones or gastrointestinal tract.
Diagnosing melanoma typically involves a skin biopsy. During this process, your doctor removes a small tissue sample from the suspicious mole or spot and sends it to a pathologist, who examines the sample and checks it for skin cancer. If the test comes back positive, then your doctor will completely remove the mole and an amount of surrounding tissue.
Additional testing will be necessary to determine the stage of the melanoma and whether it has spread to your lymph nodes or other parts of your body. These tests include a sentinel node biopsy, blood tests, molecular analyses and imaging tests, such as:
- Chest X-rays
- Computed tomography (CT) scans
- Magnetic resonance imaging (MRI) scans
- Positron emission tomography (PET) scans
Treatment Options for Melanoma
Melanoma treatment often begins with surgically removing the cancerous tissue. Doctors frequently perform this as an outpatient surgery under local anesthesia, meaning you don’t need to stay overnight in the hospital and won’t be unconscious during the procedure (but also won’t feel it happening). An ulcerated tumor will likely also need a sentinel node biopsy to determine if lymph nodes are involved. Surgeons usually set a safety margin around the tumor and remove some healthy-looking tissue. This helps them ensure that all of the cancerous growth is removed.
Treatment options for melanoma that has metastasized beyond the skin include:
- Surgical removal of any affected lymph nodes or other tissues.
- Immunotherapy treatments that help your body’s immune system fight the cancer.
- Targeted therapy, which identifies and uses drugs that are effective against your specific cancer cells.
- Radiation therapy that uses high-energy beams to kill cancer cells.
- Chemotherapy, which consists of various drugs that you take intravenously or orally to kill cancer cells.
Regular followup appointments after treatment are extremely important because they can help your doctor detect new or recurrent melanoma as early as possible. Followup care may include X-rays, blood tests and imaging tests.
Because a cancer diagnosis can be very difficult to process and also life-changing in many ways, it’s important to learn effective ways to cope with the emotional and physical changes the disease can bring up. Coping methods include learning about melanoma and the different treatment options so that you’re actively involved in your care, along with getting the support you need by keeping your relationships with close friends and family strong.
It may also be helpful to find a counselor or therapist to talk to about how you’re feeling. Your doctor may be able to suggest support groups in your area as well, and you can also locate these groups and learn additional information through the National Cancer Institute and the American Cancer Society.