What Causes Non-Melanoma Skin Cancer?

Non-melanoma skin cancer begins when abnormal cells in the tissues of the skin begin to grow and multiply. This abnormal growth is thought to be spurred by certain types of genetic changes within the cells. Nearly all types of non-melanoma skin cancers develop in the squamous and basal cells of the epidermis.

Risk Factors for Non-Melanoma Skin Cancer

A number of factors can increase a person’s chances of developing any of the non-melanoma skin cancers:

• Fair complexion and blond or red hair - People with light skin are at higher risk than darker-skinned, dark-haired persons. This is because they have lower levels of melanin in their skin. Melanin helps to protect the skin against sun damage and causes it to tan when exposed to the sun.
• Frequent tanning or sunburn - Excessive sun exposure is a major risk factor for all types of skin cancer. Exposure to ultraviolet radiation from the sun or from tanning booths can damage the skin over time and make it more susceptible to skin cancer.
• History of certain types of skin conditions:
  
  
  • Actinic keratosis - Sometimes called solar keratosis, actinic keratosis is a precancerous condition that is generally considered to be the earliest stage of skin cancer. This condition causes small, scaly, red or brown patches that are most often found on areas exposed to the sun, especially the face and the backs of the hands. Actinic keratosis may also appear as cracking or peeling of the lower lip that does not heal. More common in fair-skinned individuals who have had a lot of sun exposure, these growths may develop into squamous cell carcinoma if left untreated.
    

• Chronic skin inflammation or ulcers - Some types of chronic skin conditions can develop into cancer. These conditions include damage caused by severe, long-term, inflammatory skin diseases; scars from severe burns; and injury to the skin from an underlying bone infection. Any of these factors can increase the risk of non-melanoma skin cancer, although the risk is small compared with other factors.
• Diseases that make the skin especially sensitive to the sun - These include albinism, a genetic condition in which a person’s skin lacks the melanin that normally gives skin its color. 
• Other risk factors:
  

  • Radiation therapy - Radiation treatment that is given for another type of cancer can damage the skin where the radiation was received and lead to skin cancer.
  • Previous case of skin cancer -People who have had a previous case of either melanoma or non-melanoma skin cancer are at risk of having the cancer recur.
  • Infection with certain types of human papillomavirus - Certain types of human papillomavirus can cause cancer of the epithelial cells of the cervix.
  • A suppressed immune system - Many chemotherapy medications have the side effect of suppressing the immune system. Immune-suppressing medications are given to patients who receive organ transplants to decrease the risk that the body will reject the new organ. Patients who receive immune-suppressing drugs are at risk for developing skin cancers. Infection with HIV, the virus that causes AIDS, suppresses the immune system and also increases the risk of skin cancer.
  • Tobacco use - Any type of tobacco use, including smoking cigarettes and chewing tobacco, increases the risk of many types of cancer, including cancers of the epithelial cells of the lips and gums.
  • Chemical exposure - People who work with, or have a great deal of exposure to, certain chemicals, including arsenic and vinyl chloride, are at increased risk for developing both melanoma and non-melanoma skin cancers.

Like melanoma, non-melanoma skin cancer has been increasing in incidence each year in the United States over the past several decades. These types of cancers were once found much more often in people over 50, but are now beginning to occur more often among younger people. This may be due to the increased popularity of sun tanning outdoors and in tanning salons.

This content has been reviewed and approved by Myo Thant, MD.