title: The prevalence of familial testicular cancer: an analysis of two patient populations and a review of the literature.
abstract: BACKGROUND
  Undescended testes and antecedent testicular tumor are recognized risk factors for testicular germ cell cancer. It has been suggested that a family history of testicular cancer constitutes another major risk indicator. This postulation is mainly based on clinical observations and on very few systematic investigations. In the current study, the authors analyzed the proportion of familial testicular cancer in their study population and estimated the relative risk created by a family history of the disease.
  
  
  METHODS
  The proportion of familial testicular cancer was analyzed in a prospective 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.
authors.affiliation: Urologische Abteilung, Albertinen-Krankenhaus, Hamburg, Germany.
authors.forename: K P
authors.initials: KP
authors.lastname: Dieckmann
authors.forename: U
authors.initials: U
authors.lastname: Pichlmeier
mesh_terms: D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D013736:Testicular Neoplasms / Q000235:genetics*