Melanoma risk factors

The etiology of melanoma is multifactorial. The most important risk factor is excessive, intermittent exposure to ultraviolet light, expecially in childhood. Also among the risk factors you should consider a personal or family history of melanoma, your skin phototype, the number of melanocytic moles, immunosuppression, multiple atypical nevi, and finally giant congenital nevi.

UV light exposure: there is a close relation between melanoma and overexposure to ultraviolet (UV) radiation; UVA radiation may cause skin damage that can lead to skin cancer and premature aging. UVB radiation, which causes sunburn, can potentially lead to skin cancer.People with phototype I and II (freckles, blonde or red hair, light-colored eyes) have an higher incidence of melanoma, particularly if they live where the sun is stronger. Populations with fair skin have an incidence of melanoma 10 times higher than blacks and 7 times higher than hispanic americans. A personal history of sunburn before age 20 is associated with an increased risk.

Giant congenital nevi: persons who have with giant congenital nevi with a diameter greater than 15 cm have a 6% risk of developing melanoma and in 50% it occurs in the first 5 years of life. These melanomas are often deep and spread into subcutaneous tissue.

Atypical Moles

Multiple atypical nevi: the presence of multiple atypical or dysplastic nevi is related with a high risk of developing a melanoma (about 7 times higher than normal). It is believed that patients with dysplastic nevus syndrome, family history of atypical nevi and/or melanoma have a 100% chance of developing melanoma during their lifetime. A patient with only one atypical nevus most likely does not have an increased lifetime risk

A family history of melanoma: a family history of melanoma increases the risk of developing melanoma from 3 to 8 times. Genetic studies have identified a familial melanoma gene, CDKN2, on chromosome 9p21 that encodes a protein of tumor suppression p16.16. Mutations in this gene have been documented in 50% of patients with family history of melanoma. Approximately 32,000 people in the United States are estimated to be in this familial category

Tanning bed use: UV artificial exposure to UV rays (sun beds) for more than 10 sessions per year doubles the risk of melanoma in people over 30 years. The desire to acquire a tan for fashion or cosmetic purposes has led to a large increase in the use of artificial tanning sunbeds expecially in developed countries.

UV lamps

Immunosuppression: this factor increases the risk of developing melanoma, particularly in patients with lymphoma, AIDS, leukemia or organ transplants who get immunosoppressive drugs. Transplant recipients and lymphoma patients are far likelier than the average person to get that form of skin cancer and to die from it. That is because their immune systems tend to be significantly depressed, making early detection of melanoma even more important. The odds of getting melanoma are up to 2.5 times higher in people who have received a transplant or who have lymphoma, and melanoma also is likelier to be fatal in those patients, he adds. Patients who have the form of lymphoma called chronic lymphocytic leukemia and develop melanoma are 2.8 times more likely to die from metastatic melanoma, in which the cancer has spread from the skin to other parts of the body, such as internal organs.

Number of nevi: epidemiology studies have shown that people with numerous moles have an higher incidence of melanoma. A study shows that the number of cases of melanoma is two-fold among individuals with more than 50 nevi compared with persons that have less than15 nevi. 1 in 4 melanoma is related to a preexisting nevus.

Number of moles

Age: Adults are at greater risk of developing melanoma, although it can occur in children and adolescents.

Gender: in females, the incidence increase was triphasic, with a rapid increase between 20 and 40 years of age, a slower increase from 40 to 70 years of age, and then an increase thereafter that was not as rapid as the increase in young adults. In males there is a slower increase in 20- to 40-year-olds than in females and the most rapid increase between 50 and 80 years of age. Below age 40, the incidence in females was higher in all age subgroups than in males

Racial differences: the incidence of melanoma was highest in fair-skinned persons. In Hispanics is high the incidence of acral melanomas

Genetics: people with xeroderma pigmentosum are at greater risk for melanoma and other skin cancers on exposed areas of the skin.

Website by Dott Nicola Angelotti, Dermatologist, Massa, Italy: E mail: dermatologo@virgilio.it

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