Rising risk of testicular cancer by birth cohort in the United States from1973 to 1995

Purpose: Recent epidemiological studies have demonstrated an increasing inc idence of testicular cancer in white men which appears to be correlated wit h the period of birth. Because this birth cohort phenomenon can explain eti ological factors in testicular cancer, we determine whether this trend is p resent throughout the United States based on an analysis of testicular canc er incidence by birth cohort. Materials and Methods: Testicular cancer incidence was obtained from the Na tional Cancer Institute Surveillance, Epidemiology and End Results database from 1973 to 1995. Numbers of cases were extracted and grouped by 5-year b irth cohorts for all testicular germ cell neoplasms. Poisson regression ana lysis with variables of age, time of diagnosis and birth cohort were used t o determine relative risk. Poisson models were compared using computer log linear model software. Results: Between 1973 and 1995 the incidence of testicular cancer in the Un ited States increased 51% (3.61 to 5.44/100,000). Analysis of Poisson model s revealed that birth cohort was strongly associated with relative risk of testicular cancer (p = 0.001). In addition, peak age at diagnosis decreased for each successive birth cohort. Conclusions: The overall incidence of testicular cancer in white men and th e relative risk of testicular cancer have been increasing in the United Sta tes. This trend is strongly associated with birth cohort in concordance wit h previously reported European data. Moreover, testicular cancer is being d iagnosed at a younger age as evidenced by a shift to the left in the age of peak incidence. These unique epidemiological patterns offer a basis for an alysis of potential etiological factors.