Melanoma accounts for less than 5 percent of skin cancer cases, but is responsible for more than 75 percent of skin cancer deaths. At a time when the incidence of many cancers is falling, the rate of melanoma is rising. The World Health Organization estimates that approximately 160,000 new cases of melanoma are diagnosed each year, and that melanoma is responsible for approximately 48,000 deaths worldwide per year.
What is melanoma?
Melanoma is a cancer arising in a specialized skin cell called a melanocyte. Melanocytes produce a compound called melanin, a pigment that gives the skin its color. When exposed to UV light (ultraviolet radiation) from the sun or artificial sources such as tanning beds, the melanocytes try to protect the skin by producing more melanin, giving the appearance of a tan. With too much exposure to UV radiation, melanocytes can become damaged and start to grow abnormally, leading to melanoma.
What are the signs of melanoma?
A melanoma can first appear as a new mole (small blemish) on the skin, or as a change in the appearance of an existing mole. Physicians suggest checking the skin regularly to detect any change in existing moles, focusing on the ‘ABCDE’ warning signs. Asymmetry refers to one half of the mole looking different from the other half. Border irregularity refers to moles with notched or irregular edges. Color refers to moles that are various shades of black, tan and brown rather than a uniform shade. Diameter refers to the size of the mole; melanomas are usually larger than the size of a pencil eraser, around 6 mm. Evolving refers to a mole that is changing in size, shape and/or color over time. If any of these signs are present, the mole should be examined by a physician.
In men, the most common sites for melanoma are on the upper body and on the head and neck. In woman, melanoma most often appears on the lower legs.
Risk factors for melanoma
Some risk factors for melanoma cannot be modified. Individuals with fairer skin (particularly with lighter eyes and hair color) are at greater risk for melanoma. Family history can also play a role; approximately one in every 10 patients diagnosed with melanoma has a family member with a history of the disease.
However, the continuing rise in the incidence of melanoma does not appear to be associated with these non-modifiable risk factors, but instead with behaviors which are under individual control, namely exposure to harmful UV radiation. One of the most dangerous of these behaviors is the use of tanning beds and lamps. In 2009, the International Agency for Research on Cancer (IARC) added tanning beds to the list of the most dangerous carcinogens, or cancer causing agents. Individuals who use sunbeds before the age of 30 increase their lifetime risk of melanoma by more than 75 percent. Tanning beds expose their users to ten to fifteen times more UV radiation than the noonday sun.
Tanning bed use among children and young adults is surprisingly prevalent. Researchers in England discovered that a quarter of a million children between the ages of 11 and 17 used sunbeds regularly (prior to the enactment of new regulations in 2010). 37 percent of US females between the ages of 13 and 19 have used tanning beds.
Melanoma rates are rising sharply in young patients, particularly females
Researchers at the Mayo Clinic discovered an alarming rise in melanoma rates in patients from age 18 to age 39. Over the time period from 1979 to 2009, the incidence of melanoma increased fourfold in young men and eightfold in young women. These findings underscore the real cancer risk for younger patients; melanoma is the most common form of cancer for young adults aged 25-29.
The researchers speculated that the unexpected rise in melanoma incidence, and the different rates for males and females, could be attributable to the widespread use of tanning beds by these young women. This connection has not gone unnoticed by world health authorities: the United Kingdom, France and Germany all now ban children under 18 from using tanning beds, and multiple US states are adopting similar resolutions. Experts state that education is also critical; there is no such thing as a ‘healthy tan’, especially in the setting of tanning beds.