Skin Cancer Center

Skin cancer Causes and Risk Factors

What causes skin cancer?
It is thought that a build-up of overexposure to the sun over a period of several years leads to the development of basal cell and squamous cell skin cancers. In fact, Ultraviolet light (UVA and UVB) from the sun is ranked as the main cause of most skin cancers. Although many contributing factors exist such as heredity and environment, sunburn and ultraviolet (UV) light are the principle agents that cause damage the skin that can lead to skin cancer.

Furthermore, reduced ozone layers of the earth's atmosphere, have resulted in increased levels of UV light. Ozone serves as a filter to screen out and reduce the amount of UV light that we are exposed to. With less atmospheric ozone, a higher level of UV light reaches the earth's surface.

Risk factors
Risk factors increase the likelihood of experiencing a disease or condition. A number of different factors can combine and make it more likely that a person will experience skin cancer. For example, people with light, fair skin are more likely to develop skin cancer than those with darker skin. Other risk factors include:

Age - Half of all melanoma cases occur in people 50+. However, some melanoma cases also occur in people age 20 to 30 years.

Environment -Risk of skin cancer increases according to where you live. Ultraviolet light is stronger as elevation increases (because the thinner atmosphere at higher altitudes cannot filter UV as effectively as it does at sea level). Additionally, the rays of the sun are strongest near the equator.

Ethnicity - A fair-skinned person who tends to go red or freckle in the sun has a higher risk of developing skin cancer than someone with darker skin. Black- or brown-skinned people have a low risk of developing skin cancer. This is due to the melanin pigment in their skin that provides protection. Dark-brown or black skin, however, is not a guarantee against melanoma. African-Americans can develop this cancer. On African -Americans, skin cancer can develop on the palms of the hands, soles of the feet, under nails, or in the mouth. People with the following characteristics may be at an increased risk for melanoma:

  • a mole that has changed or is changing
  • an immunosuppressive disorder
  • blond or red hair
  • blue eyes
  • dysplastic nevi
  • inability to tan
  • fair complexion
  • many freckles
  • many ordinary moles (more than 50)

Exposure to chemicals - Another possible risk factor for non-melanoma skin cancer is overexposure to certain chemicals. This over exposure for a given person usually occurs at their work site. They should wear protective clothing if they handle these substances frequently. A list of harmful chemicals includes:

  • arsenic
  • asphalt
  • coal tar
  • creosotes
  • cutting oils
  • hair dyes
  • paraffin waxes
  • petroleum derivatives
  • pitch
  • soot

Family history - Having a family history of unusual moles (atypical nevus syndrome) or melanoma increases your likelihood of developing skin cancer.

Gender Men are two times more likely than women to develop basal cell carcinoma and three times more likely to develop squamous cell carcinoma.

Genetics - People diagnosed with certain rare hereditary conditions, such as Gorlin syndrome or xeroderma pigmentosum (XP) are at a higher risk of developing skin cancer.

Lowered immunity - People who have to take drugs which lower their immunity (immunosuppressants) are at increased risk of developing skin cancer. The reason for taking the immunosuppressants however outweighs the potential risk of skin cancer.

Previous radiotherapy treatment - Radiotherapy given to treat other conditions may sometimes cause skin cancers in the treatment area later in life.

Previous skin problems - Areas of skin that have been badly burned or have long-term inflammation have an increased risk of developing squamous cell carcinoma.

Sun exposure - The amount of time spent unprotected in the sun directly affects a person’s risk of developing skin cancer. Most people receive 50 percent of their lifetime ultraviolet (UV) exposure by 20 years of age. People who work outdoors for a living are at an increased risk of developing skin cancer because of prolonged exposure to the sun. Children and young adults who have been overexposed to the sun have an increased risk of developing some form or type of skin cancer. This will not show up until later on in life; usually after about the age of 40, and often not until their 60s or 70s. The regular use of sunlamps and sun beds contributes to the risk of developing skin cancer.

To better understand the symptoms of skin cancer, continue reading here. The next section on symptoms outlines the signs and symptoms of skin cancer for those who think that they may be experiencing the condition.

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