Risk factors are the inherited or acquired factors that increase the chance of developing cancer in a person. Several epidemiological studies have suggested a number of genetic and environmental factors that may predispose to skin cancer. A knowledge about them helps us to make necessary lifestyle choices.
Following are some skin cancer risk factors:
- History of exposure to Ultraviolet (UV) radiation: Exposure to UV radiation has been considered as the major risk factor for the development of most skin cancers. The UV exposure is mostly acquired from the sunlight or UV beds usually employed for the treatment of hypopigmented skin.
The UV rays can damage the DNA of skin cells and thereby trigger the development of skin cancer. A high cumulative exposure to UV light has been indicated as the most important factor in the development of skin cancers, especially melanoma, basal cell cancer, and squamous cell cancer. Individuals with a history of sunburns are also more susceptible to develop skin cancer.
- Fair skin, red or blond hair, and light eye color: Individuals with skin, hair, and eye color towards the lighter side (that is, those who have less melanin in their skin, hair, and eye) and had substantial exposure to sunlight are considered at increased risk of developing skin cancer.
Most cases of skin cancer are reported in Caucasians (Whites) while very few cases are observed in African Americans or Hispanics. Also, the individuals with albinism, a disorder in which people lack melanin in their skin, are at higher risk of developing skin cancer.
- Moles: Individuals with atypical moles (larger, irregular, abnormal colored mole) or congenital melanocytic nevi (especially large-size moles) are at increased risk of developing melanoma.
Thus, these moles should be checked regularly along with complete skin check-up and removed surgically right away if they start growing or changing appearance.
- Genetic cancer predisposition syndromes: Some inherited cancer predisposition syndromes (caused by a mutation in certain genes which are generally transferred from one generation to other) have been reported to be associated with the increased incidence risk of skin cancer. Following are certain examples of such genetic disorders:
- Xeroderma pigmentosum (XP) (caused by a mutation in the genes that encodes proteins involved in DNA repair process) may elevate the risk of developing skin cancers in childhood.
- Basal cell nevus syndrome or Gorlin’s syndrome usually leads to the increased incidence of the basal cell carcinoma.
- Familial atypical multiple mole melanoma syndrome (FAMMM) or Dysplastic nevus syndrome (caused by a mutation in the CDKN2A or CDK4 gene) may increase the chances of developing melanoma.
- Rothmund-Thomson syndrome and Bloom syndrome (caused by a mutation in the helicase gene) may lead to early development of squamous cell carcinoma. Werner syndrome (caused by a mutation in the helicase gene) may increase the risk of developing melanoma.
Other syndromes, such as Muir-Torre syndrome, Ferguson-Smith syndrome, and Fanconi anemia have also been implicated in enhancing the risk of developing skin cancer.
- Occupational exposure: Higher risk of developing skin cancer has been linked to chronic exposure to certain chemicals like arsenic, coal tar, paraffin, and petroleum products, generally experienced by the workers of plastic, road-construction, petroleum, dyestuffs, paint, and dry-cleaning industries.
- History of radiation treatment: Individuals who had received radiation treatment in past for the treatment of any other cancer are at higher risk of developing skin cancer in the area previously exposed to therapeutic radiation dose. The development of skin cancer may take up to 15 years, and thus, this factor is of potential concern in the case of children.
- Personal history: Individuals with a personal history of skin cancer (melanoma, basal cell carcinoma, or squamous cell carcinoma) are at higher risk of developing secondary skin cancer.
- Family history of melanoma: Individuals with a history of melanoma in close relatives are at increased risk of melanoma. About 10% of all melanoma cases are reported in such individuals.
- Weakend immune system: Individuals with a weak immune system that may be due to HIV infection, auto-immune disease, chronic use of corticosteroids, or immunosuppressants in patients who have undergone an organ/hematopoietic stem cell transplant are considered at higher risk of developing certain types of skin cancers, for example, melanoma, squamous cell carcinoma, Merkel cell carcinoma, and Kaposi sarcoma (KS).
- Human papillomavirus (HPV) or Merkel cell polyomavirus (MCV) infection: HPV is a group of about 150 DNA viruses with high-risk subtypes including HPV-16 and HPV-18 that have been reported in many cases of skin cancer, especially basal cell carcinoma and squamous cell carcinoma. HPV infection is common in some geographical locations, like some areas of Africa. MCV infection has been reported in many cases of Merkel cell carcinoma. However, all individuals with HPV or MCV infection do not develop skin cancer.
- Tobacco/Cigarette Smoking: Chronic tobacco chewing or cigarette smoking exposes the body to various carcinogens that suppress the immune system to fight against HPV infection and increase the risk of squamous cell carcinoma of the lips.
- Age and Gender: Older age individuals especially males are generally at increased risk of developing skin cancer. Older age has been linked to the build-up of UV exposure over time which may cause skin cell’s DNA to degrade. However, skin cancer is now being observed in children probably due to more time spent under the sun.
- Risk of developing certain skin cancer increases in an individual with a history of psoriasis and who had received treatment with psoralens and ultraviolet light (PUVA). Also, certain chronic skin inflammatory conditions, scars, burns, or chronic skin/bone infections may lead to the development of skin cancer in the affected area, although the risk is relatively less.
In the next section, you will read about the symptoms of skin cancer.
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