A decade-long survey of pediatric cancer rates in the United States indicates that the incidence of renal carcinoma is increasing in children and adolescents across the country.
The study was published September 8 in Pediatrics.
"Our 3 biggest findings were that the incidence of renal carcinoma is increasing among children and adolescents, there is an increasing trend for thyroid cancer in both genders, and there is an increase in the overall cancer trend among African American children and adolescents," lead author David Siegel, MD, MPH, Emory University School of Medicine, Atlanta, Georgia, told Medscape Medical News.
"And these findings are a way of highlighting what questions we need to be asking in the future and hopefully by asking these questions, we can focus our research in such a way that will help us find out more information," he added.
The researchers used data from the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results databases that represent over 94% of the US population. From these large databases, they identified cancer diagnosed among US residents from 2001 through 2009. Residents were between 0 and 19 years of age.
"We identified 120,137 childhood and adolescent cancer cases during 2001-2009 with an age-adjusted incidence rate of 171.01 per million," the authors report.
Overall, the rate of all cancers combined remained stable during that period, at an annual percent change (APC) of 0.3%.
However, among all children and adolescents, renal carcinoma rates increased significantly at an APC of 5.4%, as did thyroid cancer at an APC of 4.9%, they add.
The 1.3% observed increase in the APC in overall cancer rates for African American children and adolescents was also significant.
Renal Cancer in Adults
Dr. Siegel told Medscape Medical News that increases in renal carcinoma have been observed in US adults over the past several years as well.
"This is the first time that we are aware renal carcinoma is also increasing in children," he said. While the direct cause of this increase is not known, "in adults, there has been an association between kidney cancer and obesity, but again, we don't know if obesity is causal," he added.
Similarly, investigators have not been able to identify a direct cause for the observed increase in pediatric thyroid cancer seen between 2001 and 2009. As investigators observed, increases in thyroid cancer were especially notable among adolescents and in all regions of the United States except the Midwest.
"Again," Dr. Siegel noted, "we do know that thyroid cancer is increasing in adults and that it has been associated with a few other conditions, including obesity."
On the other hand, increasing rates of pediatric thyroid cancer, although concerning, are still very low, affecting fewer than 5000 patients between 2001 and 2009; there were only 654 cases in total in 2009, up from 446 in 2001.
As Dr. Siegel explained, the incidence of pediatric cancer among African American children and adolescents has historically been less than the national average. Essentially, what researchers are now observing is a slight shrinkage of the gap in the overall cancer incidence between African Americans and other races. However, the overall incidence of pediatric cancer among African Americans is still lower than it is for other ethnic groups.
Interestingly, melanoma rates actually decreased between 2001 and 2009, but, as Dr. Siegel cautioned, this decrease may be an artifact in the way data are collected in these databases and may not reflect a true decrease in melanoma across the decade.
"Overall, cancer rates are still very low in this population," Dr. Siegel concluded. "And as a father of a child, I take comfort in knowing that any of the changes we are finding are relatively small and the probability of any child developing cancer is unlikely."
The authors have disclosed no relevant financial relationships.
Pediatrics. Published online September 8, 2014. Abstract
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Cite this: Renal Cancer Rates Rising in US Children, Teens - Medscape - Sep 10, 2014.