Etiologic differences between seminoma and nonseminoma of the testis: a systematic review of epidemiologic studies.

Descriptive epidemiologic features of testicular cancer suggest that the etiologies of seminoma and nonseminoma of the testis differ. To address this, the authors conducted a systematic review of 150 case-control and cohort studies of the etiology of testicular cancer including 1,148 relative risk estimates, stratified by histologic subgroup, reflecting 631 exposures. Their results do not support the hypothesis that seminoma and nonseminoma have different etiologies among adolescents and young men. To date, only descriptive epidemiologic features, including incidence age patterns and incidence time trends of seminoma and nonseminoma, provide evidence suggesting different etiologies, especially among newborns, infants, and elderly men.