The overall incidence of nonmelanoma skin cancer, consisting of squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), is increasing, according to background information in the article. This increasing incidence is most likely due to a combination of factors, including increased exposure to UV light, ozone depletion, and increased surveillance. Long-term exposure to the sun resulting in photodamage is perhaps the biggest risk factor for nonmelanoma skin cancer. In the United States, approximately 800,000 new cases of BCC and 200,000 new cases of SCC were diagnosed in 2000. Nonmelanoma skin cancer generally occurs in persons older than 50 years, and in this age group, its incidence is increasing rapidly. However, little is known about its incidence in persons younger than 40 years.
Leslie J. Christenson, M.D., of Mayo Clinic, Rochester, Minn., and colleagues conducted a study to estimate the sex- and age-specific incidence of BCC and SCC in Olmsted County, Minnesota, in a young population (less than 40 years old) from the beginning of 1976 through 2003. The patients in this study have comprehensive medical records captured through the Rochester Epidemiology Project.
During the study period, 451 incident basal cell carcinomas were diagnosed in 417 patients, and 70 incident squamous cell carcinomas were diagnosed in 68 patients. Overall, the age-adjusted incidence of basal cell carcinoma per 100,000 persons was 25.9 for women and 20.9 for men. The incidence of basal cell carcinoma increased significantly during the study period among women but not among men. Nodular basal cell carcinoma was the most common histologic subtype; 43.0 percent of tumors were solely nodular basal cell carcinoma and 11.0 percent had a mixed composition, including the nodular subtype. The incidence of squamous cell carcinoma was similar in men and women, with an average age- and sex-adjusted incidence of 3.9 per 100,000 persons; the incidence of squamous cell carcinoma increased significantly over the study period among both women and men.
Comparing the change in incidence rates for basal cell carcinoma, per 100,000 persons the rate for 1976-1979 for women was 13.4; for men, 22.9, and for both sexes, 18.2. For 2000-2003, the rate for women was 31.6; for men, 26.7; and for both sexes, 29.1.
For squamous cell carcinoma, per 100,000 persons the rate for 1976-1979 for women was 0.6; for men, 1.3, and for both sexes, 0.9. For 2000-2003, the rate for women was 4.1; for men, 4.2; and for both sexes, 4.1.
"This increase [in nonmelanoma skin cancer in young adults] may lead to an exponential increase in the overall occurrence of nonmelanoma skin cancer over time as the population ages. This may mean even greater demands for health care related to nonmelanoma skin cancer. Our results also emphasize the need to focus on the prevention of skin cancer in the very young so that the increasing incidence of a potentially preventable cancer can be halted," the authors conclude.
(JAMA. 2005; 294:681-690. Available pre-embargo to the media at www.jamamedia.org.)