A report from the Mayo Clinic states that incidence rates for basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (cSCCs)–particularly cSCCs—are rising and the increase is seen disproportionately in women.
The paper, published online in Mayo Clinic Proceedings (May 15, 2017), was a review of the medical records of a population-based cohort diagnosed with non-melanoma skin cancer between Jan. 2, 2000, and Dec. 31, 2010. Investigators calculated age- and sex-adjusted incidence rates for the cohort, and compared them with estimates from previous periods.
Adjusted for age, the incidence rate for BCC (measured as cases per 100,000 person-years) was 360.0 (95% confidence interval (CI); 342.5–377.4) in men and 292.9 (95% CI, 278.6–307.1) in women. Age-adjusted cSCC incidence was 207.5 (95% CI, 193.9–221.1) in men and 128.8 (95% CI, 119.4–138.2) in women.
From the period of 1976 to 1984 to the years 2000 to 2010, there was an increase in the age- and sex-adjusted incidence of BCC to 321.2 (95% CI, 310.3–332.2) from 222.0 (95% CI, 204.5–239.5) and that of cSCC to 162.5 (95% CI, 154.6–170.3) from 61.8 (95% CI, 52.3–71.4).
As well, the anatomical distribution of these two forms of cancer has also shifted over the years. BCC distribution has shifted from the head and neck to the torso, and cSCC has shifted from the head and neck to the extremities. These changes in distribution may be due to shifts in how people are being exposed to ultraviolet (UV) radiation, the authors note.
“We know that the sun and some artificial sunlight sources give off skin-damaging ultraviolet, or UV, rays,” Dr. Christian Baum, a Mayo Clinic dermatologist and the study’s senior author, said in a press release. “This skin damage accumulates over time and can often lead to skin cancer.”
Dr. Baum noted in the release that tanning has slowed, but tanning beds still exist, and beaches will never be empty. He said that it is important that people remember that UV 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.”
The data for this study came from the Rochester Epidemiology Project’s medical records linkage system. This allowed the research team to identify nearly all of the Olmsted County, Minn., adult residents who received an initial diagnosis of BCC or cSCC during the 2000–2010 period and the comparison years.
“There is no tumor registry for these types of cancer,” said Dr. Baum, “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.”