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. Melanin is responsible for skin and hair color.
Melanoma can also involve the colored part of the eye. For information about that form of melanoma, see melanoma of the eye .
Skin cancer - melanoma
Causes, incidence, and risk factors:
There are 4 major types of melanoma:
- Superficial spreading melanoma is the most common type of melanoma. It is usually flat and irregular in shape and color, with varying shades of black and brown. It may occur at any age or body site, and is most common in Caucasians.
- Nodular melanoma usually starts as a raised area that is dark blackish-blue or bluish-red, although some are without color.
- Lentigo maligna melanoma usually occurs in the elderly. It is most common in sun-damaged skin on the face, neck, and arms. The abnormal skin areas are usually large, flat, and tan with intermixed areas of brown.
- Acral lentiginous melanoma is the least common form of melanoma. It usually occurs on the palms, soles, or under the nails and is more common in African Americans.
Melanoma can spread very rapidly. Although it is less common than other types of skin cancer, the rate of melanoma is steadily increasing. It is the leading cause of death from skin disease.
In the United States, 1 in 65 people will be diagnosed with melanoma at some point in their life. The risk of developing melanoma increases with age, but the disease also frequently affects young, otherwise healthy people. Melanoma is the number one cause of cancer death in women aged 25 - 30.
Melanoma may appear on normal skin, or it may begin at a mole or other area that has changed in appearance. Some moles present at birth may develop into melanomas.
The development of melanoma is related to sun exposure, particularly to sunburns during childhood, and is most common among people with fair skin, blue or green eyes, and red or blond hair.
Risk factors include the following:
- Family history of melanoma
- Red or blond hair and fair skin
- Presence of multiple birthmarks
- Development of precancerous lesions
- Obvious freckling on the upper back
- Three or more blistering sunburns before age 20
- Three or more years spent at an outdoor summer job as a teenager
- High levels of exposure to strong sunlight
The primary symptom of any skin cancer is usually a mole, sore, lump, or growth on the skin. Any change in appearance of a pigmented skin lesion over time is a warning sign. Also, watch for any bleeding from a skin growth.
The ABCD system may help you remember features that might be a symptom of melanoma:
- Asymmetry: One half of the abnormal area is different from the other half.
- Borders: The lesion or growth has irregular edges.
- Color: Color changes from one area to another, with shades of tan, brown, or black (sometimes white, red, or blue). A mixture of colors may appear within one lesion.
- Diameter: The trouble spot is usually (but not always) larger than 6 mm in diameter -- about the size of a pencil eraser.
The key to treating melanoma is recognizing symptoms early. You might not notice a small spot of concern if you don't look carefully, so perform thorough self-examinations monthly, and schedule a formal skin exam with a dermatologist yearly.
Signs and tests:
If you notice any suspicious skin markings, see your health care provider as soon as possible.
The American Cancer Society recommends professional skin examinations every year for people older than 40, and every 3 years for people aged 20 - 40. Monthly self-examination is also recommended.
Your health care provider may suspect melanoma based on the appearance of the growth, sore, or lump. A biopsy may be used to confirm the diagnosis. The biopsy may involve removal of a small area of a growth, or the entire growth itself.
The cancerous skin cells and a portion of the normal surrounding skin usually have to be surgically removed. A procedure called surgical lymph node biopsy may be necessary to check if the cancer has spread to nearby lymph nodes. If it has, these lymph nodes may also need to be removed. A skin graft may be necessary after the surgery if a large area of skin is affected.
Only the smallest and most shallow melanomas can be cured by surgery alone, so early diagnosis is very important. Radiation therapy , chemotherapy , or immunotherapy (use of medications that stimulate the immune system, such as interferon) may be recommended in addition to surgery.
If the skin cancer is deeper than 4 mm or the lymph nodes have cancer, there is a high risk of the cancer spreading to other tissues and organs. Treatment with interferon after surgery may be useful for these patients. Studies have suggested that interferon improves the overall chance of cure by approximately 10%.
However, interferon has many side effects and is sometimes difficult to tolerate. Patients with high-risk melanomas should consider enrolling in clinical trials. These are research studies of new medications or other treatments.
For patients with melanoma that has spread beyond the skin and lymph nodes to other organs, treatment is more difficult. At this point, melanoma is usually not curable. Treatment is usually directed at shrinking the tumor and improving symptoms. Both chemotherapy and use of interferon or interleukin may be tried. These patients also should consider participating in clinical trials.
Treatment success depends on many factors, including the patient's general health and whether the cancer has spread to the lymph nodes or other organs.
If caught early, melanoma can be cured. The risk of the cancer coming back increases with the depth of the tumor -- deeper tumors are more likely to come back. If the cancer has spread to lymph nodes, there is a greater chance that the melanoma will come back.
For melanoma that has spread to other tissues and organs, the cure rate is low. Melanoma that has spread may lead to death.
Complications of melanoma include the following:
- Spread to other organs
- Damage to deep tissue
- Side effects of treatment
- Hair loss
Calling your health care provider:
Call your health care provider if you notice any symptoms of melanoma, particularly the following:
- If any existing skin growth changes in color, size, or texture
- If an existing lesion develops pain, swelling, bleeding, or itching
Protect yourself from the sunlight's damaging ultraviolet rays. This includes the following:
- Applying a sunscreen with SPF 15 or higher, every day (during winter months as well)
- Wearing protective clothing, including hats and sunglasses
- Refraining from intentionally lying in the sun or using tanning devices
- Minimizing sun exposure
- Especially during the summer
- Particularly between the hours of 10:00 a.m. and 2:00 p.m.
References: Geller AC, et al. Screening, early detection, and trends for melanoma: current status (2000-2006) and future directions. J Am Acad Dermatol. 2007;57(4):555-572.
|Review Date: 2/5/2008|
Reviewed By: Kevin Berman, MD, PhD, Associate, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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