Melanoma is a disease in which malignant (cancer) cells form in melanocytes (cells that color the skin). The skin is the body’s largest organ. The skin has several layers, but the two main layers are the epidermis (upper or outer layer) and the dermis (lower or inner layer). Skin cancer begins in the epidermis, which is made up of three kinds of cells:
- Squamous cells: Thin, flat cells that form the top layer of the epidermis.
- Basal cells: Round cells under the squamous cells.
- Melanocytes: Cells that make melanin and are found in the lower part of the epidermis. Melanin is the pigment that gives skin its natural color. When skin is exposed to the sun or artificial light, melanocytes make more pigment and cause the skin to darken.
There are two forms of skin cancer: melanoma and nonmelanoma.
- Melanoma is a rare form of skin cancer. It is more likely to invade nearby tissues and spread to other parts of the body than other types of skin cancer. When melanoma starts in the skin, it is called cutaneous melanoma. Melanoma may also occur in mucous membranes (thin, moist layers of tissue that cover surfaces such as the lips).
- The most common types of skin cancer are basal cell carcinoma and squamous cell carcinoma. They are nonmelanoma skin cancers. Nonmelanoma skin cancers rarely spread to other parts of the body.
Melanoma can occur anywhere on the skin. In men, melanoma is often found on the trunk (the area from the shoulders to the hips) or the head and neck. In women, melanoma forms most often on the arms and legs. Being white or having a fair complexion increases the risk of melanoma, but anyone can have melanoma, including people with dark skin.
Risk factors for melanoma include the following:
- Having a fair complexion, which includes the following:
- Fair skin that freckles and burns easily, does not tan, or tans poorly.
- Blue or green or other light-colored eyes.
- Red or blond hair.
- Being exposed to natural sunlight or artificial sunlight (such as from tanning beds) over long periods of time.
- Being exposed to certain factors in the environment (in the air, your home or workplace, and your food and water). Some of the environmental risk factors for melanoma are radiation, solvents, vinyl chloride, and PCBs.
- Having a history of many blistering sunburns, especially as a child or teenager.
- Having several large or many small moles.
- Having a family history of unusual moles (atypical nevus syndrome).
- Having a family or personal history of melanoma.
- Being white.
- Having a weakened immune system.
- Having certain changes in the genes that are linked to melanoma.
Signs & Symptoms
These and other signs and symptoms may be caused by melanoma or by other conditions. Check with your doctor if you have any of the following:
- A mole that:
- changes in size, shape, or color
- has irregular edges or borders
- is more than one color
- is asymmetrical (if the mole is divided in half, the 2 halves are different in size or shape)
- oozes, bleeds, or is ulcerated (a hole forms in the skin when the top layer of cells breaks down and the tissue below shows through)
- A change in pigmented (colored) skin
- Satellite moles (new moles that grow near an existing mole)
There are five types of standard treatment. Your OHC doctor will help you determine the best care plan for you.
- Surgery to remove the tumor is the primary treatment of all stages of melanoma. A wide local excision is used to remove the melanoma and some of the normal tissue around it. Skin grafting (taking skin from another part of the body to replace the skin that is removed) may be done to cover the wound caused by surgery.
It is important to know whether cancer has spread to the lymph nodes. Lymph node mapping and sentinel lymph node biopsy are done to check for cancer in the sentinel lymph node (the first lymph node the cancer is likely to spread to from the tumor) during surgery. A radioactive substance and/or blue dye is injected near the tumor. The substance or dye flows through the lymph ducts to the lymph nodes. The first lymph node to receive the substance or dye is removed. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are found, more lymph nodes will be removed and tissue samples will be checked for signs of cancer. This is called a lymphadenectomy.
Even if the doctor removes all the melanoma that can be seen at the time of surgery, some patients may be given chemotherapy after surgery to kill any cancer cells that are left. Chemotherapy given after surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.
Surgery to remove cancer that has spread to the lymph nodes, lung, gastrointestinal (GI) tract, bone, or brain may be done to improve the patient’s quality of life by controlling symptoms.
- Chemotherapy uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. The way the chemotherapy is given depends on the type and stage of the cancer being treated.
- Radiation therapy uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. The way the radiation therapy is given depends on the type and stage of the cancer being treated. External radiation therapy is used to treat melanoma, and may also be used as palliative therapy to relieve symptoms and improve quality of life.
- Immunotherapy uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This type of cancer treatment is also called biotherapy or biologic therapy.
- Targeted therapy uses drugs or other substances to attack cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do.