Incidence of Non-melanoma Skin Cancers Steadily Increasing

In recent years, the number of new skin cancer diagnoses has risen.

For a study published in Mayo Clinic Proceedings, the authors used medical records from the Rochester Epidemiology Project to compare diagnoses of basal cell carcinoma and squamous cell carcinoma between 2000 and 2010 to diagnoses in prior years.

The investigators compared the 2000-2010 period to 1976-1984 and 1985-1992. The results of the study found that squamous cell carcinoma diagnoses increased 263% during 2000 and 2010, and basal cell carcinoma diagnoses increased 145%.

Women aged 30 to 49 years had the greatest increase in basal cell carcinoma, whereas, women aged 40 to 59 years and 70 to 79 years experienced the greatest increase in squamous cell carcinomas.

Squamous cell carcinoma diagnoses among men increased between the 1976 and 1984 period and the 1985 to 1992 period. However, there was a slight dip between 2000 and 2010.

Men over 29 years had similar increases in basal cell carcinoma diagnoses in the 2000 to 2010 period compared with the 2 earlier periods.

“We know that the sun and some artificial sunlight sources give off skin-damaging ultraviolet, or UV rays,” said senior author Christian Baum, MD. “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, the practice will never be eliminated fully. Individuals should be conscious of the fact that the damage accumulates, Dr Baum noted.

“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,” Dr Baum said.

The study also found that shifts in exposure to UV light may be why cancer tumors are forming in areas of the body not commonly found. In early years, basal cell and squamous cell carcinomas were more likely to be diagnosed on the head and neck. But in the most recent period, records show that basal cell tumors on the torso has increased, as did squamous cell carcinomas on the arms and legs.

“Use sunscreen,” Dr Baum 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 isn’t shining. UV rays bounce around under the clouds, off the sun, buildings, and more, causing damage––even on gray days.”

The Rochester Epidemiology project used in the study is a medical records linkage system and research collaborative in Minnesota and Wisconsin. The investigative team identified nearly all the adult residents of Olmsted County, MN, who received an initial diagnosis of basal or squamous cell carcinoma, or both, between 2000 and 2010 and the comparison years.

“There is no tumor registry for these types of cancer,” Dr Baum said. “So it is difficult to have accurate estimates of the national or worldwide impact of these cancers. However, because the Rochester Epidemiology Project contains health care information for virtually all residents of Olmsted County since 1966, it provides a good proxy for information on many global population health concerns.”