Risk Factors

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Risk factors for squamous cell carcinoma include:

Overexposure to UV Radiation

Overexposure to ultraviolet (UV) radiation from the sun is the single most important cause of skin cancer, including squamous cell carcinoma.

UV radiation comes from invisible rays that are part of the energy that comes from the sun. Two kinds of UV radiation are UVA and UVB radiation. According to the National Cancer Institute, UVA radiation may cause skin damage that can lead to skin cancer or premature aging. UVB radiation causes sunburn, and scientists believe these rays cause most skin cancers, including squamous cell carcinoma.

People who work outdoors, spend a lot of time at the beach, or regularly participate in outdoor sports have a greater risk of developing skin cancer. Sun lamps and tanning salons are another source of exposure to harmful UV rays and should be avoided.

Fair Skin

People with fair skin -- especially those with blond or red hair and blue or light-colored eyes -- are more likely to develop skin cancer because their skin contains less of the pigment melanin, which provides a degree of natural protection from the sun. People with dark skin, however, can develop squamous cell carcinoma.

Personal History of Skin Cancer

People who have had skin cancer are more likely to develop skin cancer again.

Other Skin Conditions

Squamous cell carcinoma can arise from certain skin conditions, including a type of precancerous lesion known as actinic keratosis, burn scars, and chronic skin ulcers.

Exposure to Industrial Compounds

Other, less common risk factors for squamous cell carcinoma include repeated exposure to radiation and exposure to coal tar, arsenic, and other industrial compounds.

Weakened Immune System

People with a weakened immune system due to illness, treatment with chemotherapy, or treatment with drugs to prevent organ transplant rejection also are at increased risk for developing squamous cell carcinoma.