history of testicular cancer constitutes another major risk indicator. This postulation is mainly based on clinical observations and on very few systematic investiga-1 Urologische Abteilung, Albertinen-Krankentions. In the current study, the authors analyzed the proportion of familial testicular haus, Hamburg, Germany.
cancer in their study population and estimated the relative risk created by a family 2 Abteilung Mathematik in der Medizin, Univershistory of the disease. ita Β¨tskrankenhaus Eppendorf, Hamburg, Ger-
METHODS.
The proportion of familial testicular cancer was analyzed in a prospecmany.
tive multicentric study involving 1692 patients. The median ages of patients with and without a family history of the disease were compared. In a different patient population consisting of 518 patients and 531 age-matched controls, the frequency of family history was investigated and the relative risk calculated. In addition, a literature survey was performed to look for previous systematic reports on familial testicular cancer.
RESULTS.
In the prospective study, 18 patients (1.1%; 95% confidence interval, 0.63-1.68%) had a first-degree relative afflicted with testicular cancer. Age at presentation was not significantly different between patients with a family history and those without. In the retrospective series, the proportion of those with a family history was 1.7% (95% confidence interval [CI], 0.80-3.27%). There was a 3.1-fold increased relative risk (95% CI, 0.77-17.95) for first-degree relatives of patients with testicular cancer. Ten previous reports on familial testicular cancer were identified in the literature. Combining the results of those previous reports and the current study led to a weighted mean prevalence of familial testicular cancer of 1.35% (95% CI, 1.12-1.58%).
CONCLUSIONS.
The current study underscores that susceptibility to testicular germ cell cancer is influenced by genetic factors. A family history of testicular cancer is encountered in about 1.35% of patients. The relative risk for first-degree relatives of patients with the disease is increased by a factor of 3-10.