THE PREVALENCE OF FAMILIAL TESTICULAR CANCER - AN ANALYSIS OF 2 PATIENT POPULATIONS AND A REVIEW OF THE LITERATURE

BACKGROUND, Undescended testes and antecedent testicular tumor are rec ognized risk factors for testicular germ cell cancer. It has been sugg ested that a family history of testicular cancer constitutes another m ajor risk indicator. This postulation is mainly based on clinical obse rvations and on very few systematic investigations. In the current stu dy, 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 te sticular cancer was analyzed in a prospective multicentric study invol ving 1692 patients. The median ages of patients with and without a fam ily history of the disease were compared. In a different patient popul ation consisting of 518 patients and 531 age-matched controls, the fre quency of family history was investigated and the relative risk calcul ated, In addition, a Literature survey was performed to look for previ ous 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 int erval [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 testi cular 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 fam ilial testicular cancer of 1.35% (95% CI, 1.12-1.58%). CONCLUSIONS. Th e current study underscores that susceptibility to testicular germ cel l cancer is influenced by genetic factors. A family history of testicu lar cancer is encountered in about 1.35% of patients. The relative ris k for first-degree relatives of patients with the disease is increased by a factor of 3-10. (C) 1997 American Cancer Society.