Nonmelanoma skin cancers on the rise

Volume 6, Issue 3, 2017


An increase in basal cell carcinoma and squamous cell carcinoma renews the call for caution in tanning.

Photograph of Christian L. Baum, M.D.

Christian L. Baum, M.D.

New diagnoses of two types of skin cancer have increased in recent years, according to a Mayo Clinic-led team of researchers.

The research team's skin cancer findings were published in a research paper in the June 2017 issue of Mayo Clinic Proceedings.

The researchers used medical records from the Rochester Epidemiology Project to compare the number of diagnoses of basal cell carcinoma and squamous cell carcinoma between 2000 and 2010 to the number of diagnoses in prior years. The Rochester Epidemiology Project is a medical records linkage system and research collaborative based in Minnesota.

The researchers reported that between 2000 and 2010, diagnoses of squamous cell carcinoma (also called cutaneous squamous cell carcinoma) increased 263 percent and diagnoses of basal cell carcinoma increased 145 percent. Researchers compared the 2000-2010 time period to the time periods of 1976-1984 and 1985-1992.

Both basal cell carcinoma and squamous cell carcinoma are types of nonmelanoma skin cancer.

Women ages 30 to 49 experienced the greatest increase in basal cell carcinoma diagnoses, according to the study findings. Women ages 40-59 and 70-79 experienced the greatest increase in squamous cell carcinomas.

Men had an increase in squamous cell carcinomas between the first and second time periods studied (1976-1984 and 1985-1992) but experienced a slight decline in the 2000-2010 time period. However, for basal cell carcinomas, men older than age 29 showed similar increases in diagnoses in the 2000-2010 period as in the two earlier periods of time.

"We know that the sun and some artificial sunlight sources give off skin-damaging ultraviolet (UV) rays," said Christian L. Baum, M.D., a Mayo Clinic dermatologist in Rochester, Minnesota, and senior author of the Proceedings skin cancer research paper. "This skin damage accumulates over time and can often lead to skin cancer. Despite the fact that sunscreens and cautionary information have been widely available for more than 50 years, we saw the emergence of tanning beds in the 1980s, and tanning — indoors or out — was a common activity for many years."

Although tanning has slowed, tanning beds still exist, and beaches will never be empty, Dr. Baum noted. "But what people should remember is that the damage accumulates, and eventually those blistering sunburns of your youth and hot, reddened skin and peeling shoulders of your adulthood can add up to one or more skin cancers," he said.

The paper's authors also reported that shifts in exposure to UV light may be the reason for a shift in where the skin cancer tumors are found on the body.

In the study's two earlier time periods, both basal cell carcinoma and squamous cell carcinoma were diagnosed more often on the head and neck. But in the most recent study time period, records showed that basal cell tumors on the torso increased and squamous cell carcinomas increased on the arms and legs.

According to Dr. Baum, the risk of cancer should provide the ultimate argument for using sunscreen — every day, year-round on all exposed skin.

"Use sunscreen," he said. "This includes on your left arm for those who do a lot of driving. UV rays can penetrate car windows and exposed skin, even when the sun is not shining. UV rays bounce around under the clouds, off the snow, buildings and more, causing damage even on gray days."