In both sexes, GCTs occurred most frequently in the gonads, with yolk sac tumours being the most common histological subtype, followed by other non-seminomas in males and teratomas in females. The distribution of age at diagnosis was bimodal, with peaks observed before the age of 5 years and after the age of 10 years in both sexes ().
Characteristics of paediatric GCT diagnoses
No statistical differences were found between cases and controls with respect to gestational age, birth weight, or maternal age. Control mothers were more educated and more likely to be of white race than were case mothers. A higher frequency of cases had household incomes below $20
000 than did controls ().
Infant and parental sociodemographic characteristics of cases and controls
In males, there were statistically significant increased risks of GCTs in association with any CA (OR=2.5, 95% CI: 1.3–4.9), which was mainly because of cryptorchidism (OR=10.8, 95% CI: 2.1–55.1). The risk of GCTs increased significantly with increasing number of CAs in males (P for trend=0.01). There were no other significant associations between GCTs and CAs in either sex (). Models that included the variables shown in did not materially change the results (data not shown).
There were no significant associations between CAs and GCTs in children
2 or >2 years, except for cryptorchidism, in which risks were similar (OR2 years
=8.2, 95% CI: 0.9–72.7; OR>2 years
=14.6, 95% CI: 1.4–152.2) (data not shown).
Individuals with any CA had a significantly increased risk for extragonadal GCTs (OR=1.7, 95% CI: 1.0–2.9), with a significantly positive linear trend with increasing number of CAs (P
=0.009) (Supplementary Table 1
). Statistically significant increased risks were observed for GCTs in association with cryptorchidism for gonadal (OR=19.9, 95% CI: 3.5–111.9) but not for extragonadal (OR=3.0, 95% CI: 0.3–34.7) GCTs. For extragonadal GCTs, significant increased risks were found in association with mental retardation (OR=15.8, 95% CI: 1.4–178.0), congenital heart defects (OR=2.7, 95% CI: 1.1–6.0), and skeletal defects (OR=5.0, 95% CI: 1.3–19.1). No significant associations were observed between GCTs and CAs in analyses stratified by histological subtype (seminoma, yolk sac tumour, teratoma, and other non-seminomas), with the exception of cryptorchidism, which increased the risk for seminomas (OR=57.0, 95% CI: 1.9–∞), yolk sac tumours (OR=11.1, 95% CI: 1.6–75.6), and other non-seminomas (OR=14.8, 95% CI: 1.5–147.4). Cryptorchidism was not reported in any males with teratomas (n
=14) (data not shown).