Description, Causes and Risk Factors:
Melanoma is the most dangerous type of skin cancer. It is the leading cause of death from skin disease. It involves cells called melanocytes, which produce a skin pigment called melanin, which is responsible for skin and hair color.
About 7000 people in the UK get diagnosed with melanoma each year. It is more common in women then men. It is a very rare cancer in children, but it is the second most common cancer in people aged 15 to 34.
Experts believe that many cases of melanoma are caused by excessive exposure to ultraviolet (UV) radiation from the sun. UV rays damage DNA, the genetic material that makes up genes. Genes control the growth and health of skin cells. If the genetic damage is severe, a normal skin cell may begin to grow in the uncontrolled, disorderly way of cancer cells.
Five to 12 percent of malignant melanoma develops in individuals with more than one first-degree relative exhibiting the disease. Familial malignant melanoma is postulated to be an autosomal dominant condition. The main gene associated with this disease is CDKN2A (cyclin-dependent kinase inhibitor 2A), which maps to chromosomal region 9p21. Mutations in the CDK4 gene, mapping to 12q14, have also been found in some patient.
Use of tanning devices.
Exposure to chemicals that can cause cancer, such as arsenic, coal tar, and creosote.
Large numbers of benign naevi.
People with weaken immune system.
Clinically atypical naevi.
Early years in a tropical climate.
A mole that:
Has irregular edges or borders.
Is more than 1 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).
Change in pigmented (colored) skin.
Satellite moles (new moles that grow near an existing mole).
Changes in size, shape, or color.
Doctors use a couple different stages to classify a tumor, depending on how far it is progressed at the time of diagnosis. TNM (tumor, node, and metastasis) categorizes the cancer by the size of the tumor, the extent to which it is metastasized and the degree to which it is colonized the lymph nodes.
Stage II: Primary melanomas that are somewhat larger but which also lack ulceration, lymph node involvement, or metastases.
Stage III: Metastasis to the lymph nodes, or in-transit metastases/satellites, with no distant metastases.
Stage IV: Distant metastases. Melanomas which progress to this stage are frequently fatal.
Stage I: Primary melanoma of a certain size without ulceration, no lymph node involvement, and no metastases (secondary tumors.)
Another common way to classify malignant melanoma is using the Clark level of invasion classification. Level I means the cancer is still confined to the epidermis (the outermost layer of the skin), while level V means the tumor has grown deep into the skin and invaded the subcutaneous tissue, the fatty layer beneath the dermis.
The following tests and procedures may be used in diagnosis:
Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. For melanoma, the blood is checked for an enzyme called lactate dehydrogenase (LDH).
Wide local excision: A surgical procedure to remove some of the normal tissue surrounding the area where melanoma was found, to check for cancer cells.
Lymph node mapping and sentinel lymph node (SLN) biopsy: Procedures in which a radioactive substance and/or blue dye is injected near the tumor. The substance or dye flows through lymph ducts to the sentinel node or nodes (the first lymph node or nodes where cancer cells are likely to have spread). The surgeon removes only the nodes with the radioactive substance or dye. A pathologist then checks the sentinel lymph nodes for cancer cells. If no cancer cells are detected, it may not be necessary to remove additional nodes.
CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. For melanoma, pictures may be taken of the chest, abdomen, and pelvis.
MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body.
PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
Treatment of melanoma depends on the disease stage, the individual's age, overall health, and other factors. Doctors usually develop an individualized treatment plan for each patient.
Melanoma treatment often requires a team of specialists. The team may include:
Medical oncologist (cancer specialist).
Dermatologis (skin specialist).
Surgery to remove the tumor is the first treatment used in about 95 percent of melanoma cases. Surgery may be all the treatment needed for small, thin melanomas.
Radiation: Radiation treatment for melanomas is typically used after surgical removal of the cancerous tissue, but is sometimes used before and after the surgery. Radiation therapy is used to kill cancerous cells.
When melanoma is more advanced, other treatments such as chemotherapy (treatment with anticancer drugs) or immunotherapy may be used after surgery to kill cancer cells remaining in the body. Chemotherapy is generally used after surgical removal of the cancerous growth, and after a round of radiation. While radiation is used to kill cancer cells, chemotherapy is used to keep any remaining cells from spreading.
Disclaimer: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
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