ASK THE EXPERT: Is sun exposure the only cause of skin cancer?

By Amy Amonette Huber, MD

Dr. Huber is a board-certified dermatologist and fellowship trained MOHS surgeon.  She practices at the Memphis Dermatology Clinic in Memphis, Tennessee. Dr. Huber is a member of the American Academy of Dermatology, the American College of MOHS Surgery, The Skin Cancer Foundation's Amonette Circle and the Dermatology Foundation's Annenberg Circle.  Dr. Huber has served as a board member for the Women's Dermatologic Society.

Q: Is sun exposure the only cause of skin cancer? Is the place on your body where you’ve been sunburned the only place where skin cancer will develop?

A: While there is a definite causal relationship between UV exposure and the development of skin cancer, the relationship depends on the type of exposure, the kind of skin cancer, and the person's skin type.

Anyone can get skin cancer, although some people are at a greater risk than others.  People with lighter skin color, light hair and light eyes are more at risk, because they have less melanin in their skin to protect them.  People who have long-term, unprotected sun exposure — chronic sun exposure — are at an increased risk.

The two most common nonmelanoma skin cancers, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are directly correlated with sun accumulation over many years.  Indeed, the most common locations for BCC and SCC tumors are sun-exposed areas: the face, ears, hands, etc.  However, it is not unheard of for a BCC or SCC to appear on a non-sun-exposed area of the body.

Melanoma is different.  The sun exposure pattern believed  to result in melanoma is that of brief, intense exposure — a blistering sunburn — rather than years of tanning.  (Some studies now indicate that BCC also may be triggered by this exposure pattern.)  Other risk factors are also associated with melanoma, such as a family history and having a large number of sizable moles on the body.  Like nonmelanoma skin cancer, melanoma can arise on any area of the body, regardless of whether or not a sunburn occurred in that location.

However, sun protection remains a crucial component to preventing skin cancer.  Sunscreens that block both UVA and UVB rays are helpful, as are sun-protective clothes.  In addition to sun protection, skin self-exams are important in detecting new, suspicious lesions. The earlier a skin cancer is identified, the easier it is to treat.

Published in the Spring 2007 Edition of Sun & Skin News