Epidemiology of familial prostate cancer: 4-year assessment of French studies.

Objectives : (I) To determine the frequency of familial (at least 2 cases) and hereditary forms of prostate cancer (CaP), (2) to define the results ac cording to the patient's age at diagnosis, us various epidemiological studi es have demonstrated a possible familial aggregation of CaP in about 15 to 25% of cases. Cartel's familial segregation study (P.N.A.S. 1992, 89, 3367- 71) showed that a generic predisposition, with autosomal dominant transmiss ion, could be responsible for 9% of all cases of prostate cancel: Material and Methods : We conducted a systematic genealogy study of patient s suffering from newly diagnosed CaP or followed for known (CaP in 3 French urological centres, by means of questionnaires completed by the patients. Subsequently, a national collection of families with at least 2 cases of Ca P identified families with hereditary forms of CaP Hereditary cases were co nsidered to be those presenting at least: one CaP in three Ist degree relat ives, or 3 cases over 3 generations in the same branch of the family (pater nal or maternal), or finally 2 early cases before the age of 55 years. Stat istical analysis used the univariate logistic regression test between famil y status and the medical centre or the patient's age at diagnosis. Results : Front July 1994 onwards, we included 801 patients tall stages com bined) in the systematic study and IIO patients (13.7%) were excluded (refu sal to participate, advanced age). For 691 of the families studied (Brest: 225, Nancy: 249, Paris St Louis: 217), we observed 32 (14.2%), 29 (11.6%), 37 (17.1%) of familial forms (mean: 14.2%) and 11 (4.9%), 6 (2.4%), 8 (3.7% ) of hereditary forms (mean: 3.6%), respectively (no significant difference s between centres). Analysis of the results according to age at diagnosis o f CaP also showed a higher incidence of familial (significant difference) a nd hereditary forms (limit of significance)for CaP occurring at a younger a ge (before 65 years). The national collection collected a total of 624 fami lial forms of CaP, including 236 (37.8%) cases of hereditary forms; 115 fam ilies were informative for the genetic linkage study. Conclusion : These results confirm the data of earlier studies, revealing a bout 15 to 25% of familial forms of CaP and 5 to 10% of hereditary forms. S imilarly, the systematic study confirmed the earlier onset of CaP in patien ts with a genetic predisposition. These data therefore encourage systematic questioning of patients for a family history of CaP in order to propose ta rgeted screening of high-risk subjects in the families concerned and to int ensify identification of hereditary forms in order to investigate the genes involved.