Pediatric germ cell tumor incidence increasing in certain subgroups

The incidence of germ cell tumors in certain pediatric populations has increased during the past few decades, especially in girls aged birth to 9 years and adolescent boys aged 10 to 19 years.

Jenny N. Poynter, PhD, of the Masonic Cancer Center, University of Minnesota, Minneapolis, and colleagues used data from the NCI’s SEER registry to analyze the incidence and survival of pediatric and adolescent patients with germ cell tumors. All first malignancies in people aged younger than 19 years from 1975 to 2006 were included.

The researchers analyzed the data overall, and stratified it by age, race and ethnicity. They also looked at incidence and survival according to tumor location and histology. According to background information included in the study, germ cell tumors are normally classified into two broad groups: seminomas, including seminomas of the testes and dysgerminomas of the ovaries; and nonseminomas, such as yolk sac tumors, teratomas, embryonal carcinomas and choriocarcinomas.

In the SEER registry, there were 1,140 boys and 970 girls with malignant germ cell tumors. Although gonadal and extragonadal tumors were equal in boys aged younger than 4 years, in boys aged older than 10 years, most tumors were of the testes. For girls, most tumors in the younger group were extragonadal tumors; in the older group, tumors were mostly located in the ovaries.

The researchers did not identify a statistically significant difference in the incidence of germ cell tumors in children younger than 10 years by race. However, within each race category, differences were observed.

In whites, girls were less likely than boys to have germ cell tumors when aged 10 to 19 years (RR=0.47). The incidence was similar between boys and girls younger than 9 years. In blacks, girls were more likely to have germ cell tumors than boys younger than 9 years (RR=2.01) and those aged 10 to 19 years (RR=3.3).

Boys aged 9 years and younger and girls aged 10 to 19 years did not have an increased incidence of germ cell tumors. However, boys aged 10 years and older had a statistically significant increase in the incidence of these tumors (annual percentage change=1.2). In addition, girls aged birth to 9 years also had an increased incidence (APC=1.9).

Overall, 5-year survival rates were high in all age groups with germ cell tumors.

Poynter JN. Cancer. 2010:doi:10.1002/cncr.25454.

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