Melanoma, the most serious type of skin cancer, develops in the cells (melanocytes) that produce melanin — the pigment that gives your skin its color. Melanoma can also form in your eyes and, rarely, in internal organs, such as your intestines.
The exact cause of all melanomas isn't clear, but exposure to ultraviolet (UV) radiation from sunlight or tanning lamps and beds increases your risk of developing melanoma. Limiting your exposure to UV radiation can help reduce your risk of melanoma.
The risk of melanoma seems to be increasing in people under 40, especially women. Knowing the warning signs of skin cancer can help ensure that cancerous changes are detected and treated before the cancer has spread. Melanoma can be treated successfully if it is detected early.
Skin cancer screening
Ask your doctor whether you should consider periodic screening for skin cancer. You and your doctor may consider screening options such as:
- Skin exams by a trained professional. During a skin exam, your doctor conducts a head-to-toe inspection of your skin.
- Skin exams you do at home. A self-exam may help you learn the moles, freckles and other skin marks that are normal for you so that you can notice any changes. It's best to do this standing in front of a full-length mirror while using a hand-held mirror to inspect hard-to-see areas. Be sure to check the fronts, backs and sides of your arms and legs. In addition, check your groin, scalp, fingernails, soles of your feet and spaces between your toes.
Some medical organizations recommend periodic skin exams by your doctor and on your own. Others don't recommend skin cancer screening exams because it's not clear whether screening saves lives. Instead, finding an unusual mole could lead to a biopsy, which, if the mole is found to not be cancerous, could lead to unnecessary pain, anxiety and cost. Talk to your doctor about what screening is right for you based on your risk of skin cancer.
Sometimes cancer can be detected simply by looking at your skin, but the only way to accurately diagnose melanoma is with a biopsy. In this procedure, all or part of the suspicious mole or growth is removed, and a pathologist analyzes the sample.
Biopsy procedures used to diagnose melanoma include:
- Punch biopsy. During a punch biopsy, your doctor uses a tool with a circular blade. The blade is pressed into the skin around a suspicious mole, and a round piece of skin is removed.
- Excisional biopsy. In this procedure, the entire mole or growth is removed along with a small border of normal-appearing skin.
- Incisional biopsy. With an incisional biopsy, only the most irregular part of a mole or growth is taken for laboratory analysis.
The type of skin biopsy procedure you undergo will depend on your situation. Doctors prefer to use punch biopsy or excisional biopsy to remove the entire growth whenever possible. Incisional biopsy may be used when other techniques can't easily be completed, such as if a suspicious mole is very large.
If you receive a diagnosis of melanoma, the next step is to determine the extent (stage) of the cancer. To assign a stage to your melanoma, your doctor will:
- Determine the thickness. The thickness of a melanoma is determined by carefully examining the melanoma under a microscope and measuring it with a special tool (micrometer). The thickness of a melanoma helps doctors decide on a treatment plan. In general, the thicker the tumor, the more serious the disease.
- See if the melanoma has spread. To determine whether your melanoma has spread to nearby lymph nodes, your surgeon may recommend a procedure known as a sentinel node biopsy.
During a sentinel node biopsy, a dye is injected in the area where your melanoma was removed. The dye flows to the nearby lymph nodes. The first lymph nodes to take up the dye are removed and tested for cancer cells. If these first lymph nodes (sentinel lymph nodes) are cancer-free, there's a good chance that the melanoma has not spread beyond the area where it was first discovered.
Cancer can still recur or spread, even if the sentinel lymph nodes are free of cancer.
Other factors may go into determining the aggressiveness of a melanoma, including whether the skin over the area has formed an open sore and how many dividing cancer cells are found when looking under a microscope.
Melanoma is staged using the Roman numerals I through IV. A stage I melanoma is small and has a very successful treatment rate. But the higher the numeral, the lower the chances of a full recovery. By stage IV, the cancer has spread beyond your skin to other organs, such as your lungs or liver.
The best treatment for you depends on the size and stage of cancer, your overall health, and your personal preferences.
Treating early-stage melanomas
Treatment for early-stage melanomas usually includes surgery to remove the melanoma. A very thin melanoma may be removed entirely during the biopsy and require no further treatment. Otherwise, your surgeon will remove the cancer as well as a border of normal skin and a layer of tissue beneath the skin. For people with early-stage melanomas, this may be the only treatment needed.
Treating melanomas that have spread beyond the skin
If melanoma has spread beyond the skin, treatment options may include:
- Surgery to remove affected lymph nodes. If melanoma has spread to nearby lymph nodes, your surgeon may remove the affected nodes. Additional treatments before or after surgery also may be recommended.
- Chemotherapy. Chemotherapy uses drugs to destroy cancer cells. Chemotherapy can be given intravenously, in pill form or both so that it travels throughout your body.
Chemotherapy can also be given in a vein in your arm or leg in a procedure called isolated limb perfusion. During this procedure, blood in your arm or leg isn't allowed to travel to other areas of your body for a short time so that the chemotherapy drugs travel directly to the area around the melanoma and don't affect other parts of your body.
- Radiation therapy. This treatment uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation therapy may be recommended after surgery to remove the lymph nodes. It's sometimes used to help relieve symptoms of melanoma that has spread to another area of the body.
- Biological therapy. Biological therapy boosts your immune system to help your body fight cancer. These treatments are made of substances produced by the body or similar substances produced in a laboratory. Side effects of these treatments are similar to those of the flu, including chills, fatigue, fever, headache and muscle aches.
Biological therapies used to treat melanoma include interferon and interleukin-2, ipilimumab (Yervoy), nivolumab (Opdivo), and pembrolizumab (Keytruda).
- Targeted therapy. Targeted therapy uses medications designed to target specific vulnerabilities in cancer cells. Side effects of targeted therapies vary, but tend to include skin problems, fever, chills and dehydration.
Vemurafenib (Zelboraf), dabrafenib (Tafinlar) and trametinib (Mekinist) are targeted therapy drugs used to treat advanced melanoma. These drugs are only effective if your cancer cells have a certain genetic mutation. Cells from your melanoma can be tested to see whether these medications may help you.