The incidence of melanoma among American children and teens decreased by approximately 12% from 2004 to 2010, with the decline most notable for adolescents. The findings were published online in the Journal of Pediatrics.

In a review of data from the period of 2000-2010, Dr. Laura Campbell of Stanford (Calif.) University and her colleagues at Case Western Reserve University in Cleveland found an overall reduction in melanoma diagnoses of 11.58% per year for the period of 2004-2010 (J. Pediatr. 2015 [doi: 10.1016/j.jpeds. 2015.02.050]).

The study was conducted at Case Western Reserve University, and the researchers used the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER-18) registry to examine trends in the incidence of pediatric melanoma.

Of note, the number of new melanoma cases decreased significantly (approximately 11%) among 15- to19-year-olds between 2003 and 2010. In addition, the overall incidence of melanoma decreased significantly (7%) among boys between 2000 and 2010.

The data revealed significant decreases for the number of new cases of melanoma on the trunk (15% per year from 2004 to 2010) and upper extremities (5% from 2000 to 2010).

Dr. Campbell and her colleagues determined that a melanoma diagnosis was equally likely for male and female patients, and was more common in older than in younger patients. White patients had by far the greatest incidence of melanoma, with 97% of the overall diagnoses; 90% of the cases were in non-Hispanic whites. Superficial spreading melanoma was the most common type of melanoma, at 31%, though nodular histology was seen almost as frequently in the 0- to 9-year-olds. This younger group was more likely to have thicker tumors, ulceration, lymph node involvement, and distant metastases.

Drawing on this large registry allowed researchers more confidence that they were identifying true trends in melanoma incidence, Dr. Campbell noted.

The reasons for this decrease, which stands in contrast to earlier data showing increased incidence rates of pediatric melanoma, were not examined in this study. However, Dr. Campbell drew on these earlier studies, as well as some international studies, to identify the potential contribution of public health campaigns advocating sun protection. These campaigns began in the 1990s in the United States, and would have benefited the 15- to 19-year olds in the SEER-18 data, in whom melanoma incidence decreased beginning in 2003. Some Swedish and Australian studies showing decreased melanoma cases were confounded by an immigration-driven decrease in the highest risk light-skinned population, noted Dr. Campbell; however, the quality of the SEER-18 data allowed researchers to account for this variable, she said.

Although the widespread adoption of sun-protective behaviors (wearing hats and protective clothing, using sunscreen appropriately, and avoiding midday sun exposure) may have accounted for some of the reduction in pediatric melanomas, other societal changes may have been at play.

“We hypothesize that there has been a shift in youth participating increasingly in indoor activities, such as television/electronic devices, which may be decreasing their UVR exposure,” Dr. Campbell said.