Familial aggregation of breast/ovarian cancer: age of onset along subsequent generations in Brazil A g regação familiar de câncer de mama e ovário: idade de manifestação em gerações subseqüentes no Brasil

Antecedents of familial aggregation of breast and ovarian cancer are observed in only 5-8% of all breast cancer cases. Ne ve rt h e l e s s , this variable displays one of the highest risk ra t i o s associated to breast cancer outcome. Despite recent identification of genetic mutations associated with familial aggregation of these tumors, mainly at BRCA1 and BRCA2 genes, k n owledge on the interaction between environmental agents in these families remains quite unclear. In this paper we ascertained the correlation among ages of the onset of bre a s t / ovarian cancer in 260 Brazilian families with those cancer aggre g a t i o n . Fu rther we estimated the median age of the onset of breast cancer among four genera t i o n s . We observed that the higher the number of family cancer cases, the highest is the correlation of ages for the onset of breast cancer. We also observe d a 8-10 year decline in the mean age-of-onset of bre a s t / ovarian cancer from one generation to another in the studied families. If these results could be confirmed elsew h e re , we believe that the hypothesis of interaction between environmental risks factors in families indeed show i n g b re a s t / ovarian cancer aggregation is re i n f o rc e d .