This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on May 27, 2022.
Melanoma is an aggressive form of skin cancer. Below are some common questions and answers about the basics of the disease, its symptoms, prevention and risk factors.
Melanoma develops when damaged melanocyte cells grow uncontrollably.
Melanocytes are found mostly along the bottom of the epidermis, the outer layer of skin. These cells contain a pigment called melanin, which darkens the skin when it is exposed to ultraviolet (UV) radiation from the sun or tanning beds. Melanocytes absorb UV light, protecting the skin from burning and blocking UV light from penetrating more deeply into the skin and to internal organs. Overexposure to UV light may not only burn the skin, but damage melanocytes, causing cellular mutations that make the cells grow uncontrollably and, sometimes, travel to other parts of the body. Melanoma accounts for about 2 percent of the more than 3.5 million cases of skin cancer diagnosed each year, but it is responsible for most skin cancer deaths. Calculated separately, melanoma is the fifth most common type of cancer, accounting for more than 85,000 new cases a year, according to the National Cancer Institute.
What are the signs and symptoms of melanoma?
It may be difficult to tell if a spot or growth on the skin is a mole, a benign growth, non-melanoma skin cancer or melanoma. Like most skin cancers, melanoma may appear as a dark, painless spot or sore on the skin. The spot may change shape and color and bleed as it develops. Unlike most skin cancers, melanoma may develop on parts of the body not normally exposed to the sun, such as the groin, armpits or bottoms of the feet. Rare cases of melanoma may also be found in the eye. About 2,500 cases of ocular melanoma are diagnosed each year. Experts recommend that suspicious or fast-growing spots be checked by a doctor. The Skin Cancer Foundation provides a body map to help you keep a record of suspicious spots, and advises that you bring it with you when seeing a dermatologist or other doctor for your annual physical.
How can I tell the difference between melanoma and other forms of skin cancer?
The ABCDE method may help you determine if an abnormal growth on your skin may be melanoma.
Asymmetry: The mole has an irregular shape.
Border: The edge is not smooth, but irregular or notched.
Color: The mole has uneven shading or dark spots.
Diameter: The spot is larger than the size of a pencil eraser.
Evolving or Elevation: The spot is changing in size, shape or texture.
The only way to be sure if a mole is melanoma is to have it examined by a doctor.
Can I reduce my risk of getting melanoma?
Exposure to UV radiation is the primary cause of cell damage that may lead to skin cancer, including melanoma. Most of the UV light that reaches the earth is UVA, the long-wave ultraviolet rays that penetrate the skin more deeply than UVB (short-wave) rays. These strong rays can reach into the skin’s outer layer, where melanocytes are located.
One important way to reduce your risk of skin cancer and melanoma is to avoid sun exposure when possible and/or protect yourself from damaging rays. Consider following these tips:
How do I examine myself for skin cancer?
Take the time once a month to examine your body, literally from head to toe. It helps if you have a large or full-length mirror and a hand-held mirror. Starting with the top of your head, look for new spots, irregular or raised spots or spots that have changed or grown since your last exam. Use the hand-held mirror to look behind your ears, the back of your neck and the top of your scalp. Ask a partner or spouse to look at your back, the backs of your knees or other places that are hard to see. Don’t forget to check the soles of your feet and between your fingers and toes. Consider using a body map to keep a record of suspicious spots, and bring it to a dermatologist or other doctor for your annual physical.
Treatment for melanoma may depend on the stage of melanoma, how early it is diagnosed and whether it has metastasized. Below are answers to some common questions about available treatments for melanoma:
What are my melanoma treatment options?
Surgery to treat localized melanoma may require a wide excision and the removal of lymph nodes. In a wide excision, a surgeon will remove a large perimeter around the melanoma spot on the skin. This surgery may also cut more deeply into the skin than procedures for other types of skin cancer. Reconstructive or plastic surgery may be considered if the surgery results in scarring or disfigurement. If the melanoma has metastasized, or traveled to distant organs or other areas of the body, surgery may be required to remove metastatic tumors. Chemotherapy, radiation therapy, targeted therapy and immunotherapy are all treatment options for metastatic melanoma.
What side effects can I expect from my treatment?
Surgical procedures for melanoma may be painful and cause swelling, bruising and/or nerve damage. Surgery to remove lymph nodes may result in swelling, caused by the buildup of lymphatic fluid, a condition known as lymphedema. Chemotherapy, targeted therapy and immunotherapy drugs may cause a variety of side effects, such as nausea and vomiting, fatigue, nerve damage, mouth sores and rashes. Patients who undergo radiation therapy may experience skin irritation and/or radiation burns.
What types of doctors will I see during my treatment for melanoma?
Depending on your stage of melanoma, your care team may include a number of physicians, including one or all of the doctors below:
Below are some important questions melanoma patients should ask their doctors:
What does it mean that my cancer has metastasized?
Melanoma is more prone to travel (metastasize) than most skin cancers. Melanoma cells most often travel to the lungs, liver, bones and brain. Tumors found in those locations are still considered melanoma. For example, melanoma found in the brain is called metastatic melanoma or melanoma with brain metastases. A procedure called a sentinel lymph node biopsy may be performed to help determine if melanoma has spread. In this procedure, a surgeon removes one or more lymph nodes that may have received lymph fluid draining from the tumor. If the sentinel lymph node shows no sign of cancer, then no additional lymph node surgery may be necessary. However, if melanoma cells are found in one or more sentinel lymph nodes, then the remaining lymph nodes in the region may be removed.
Is immunotherapy an option for me?
Immunotherapy drugs called checkpoint inhibitors have been approved to treat certain types of melanoma. These drugs work by disrupting chemical signals that cancer cells send to help hide from the immune system. The U.S. Food and Drug Administration has approved certain checkpoint inhibitor drugs to treat melanoma. Immunotherapies, though, are not recommended for all patients, so talk to your oncologist about whether you are a candidate for these drugs.
Should I participate in a clinical trial?
Cancer treatments have improved tremendously over the years, thanks to advances made possible because of patients who have participated in studies exploring new treatment options, drug protocols or other approaches before they were granted federal approval. These clinical trials may offer participants new treatment options that may have otherwise been unavailable to them, especially after exhausting conventional treatments. If you are interested in participating in a clinical trial, ask your doctor whether you qualify, and discuss any concerns or questions you may have, to help you determine whether it’s a good fit for you.
Next topic: What are the facts about melanoma?