Background: Increasing scientific and public interest in hereditary cancer syndromes has created a need for estimates of lifetime cancer risks among members of families with such syndromes.
Methods: Data from the Gilda Radner Familial Ovarian Cancer Registry were used to evaluate risk for cancers of the breast, cervix, uterus, colorectum, and prostate in members of 143 families containing three or more reported cases of ovarian cancer among first- or second-degree relatives. These risks were compared with those that were expected based on general population rates obtained from the Connecticut Tumor Registry.
Results: Overall, family members' risk of cancer at any nonovarian site was 1.5 times that of the general population (P < 0.001). Among female members, risk for cancer of the breast was 2.5 times that of the general population. Risk for cancer of the uterus was 5 times that of the general population and increased with increasing number of first-degree relatives with ovarian cancer. Among male family members having three or more first-degree relatives with ovarian cancer, prostate cancer risk was 4.5 times that of the general population. No excess risks were observed for cancer of the colorectum.
Conclusions: These data support previous reports of coaggregation of cancer of the breast, uterus and ovary, and suggest coaggregation between cancer of the ovary and prostate. Differences in cancer risk profiles observed in these families with multiple ovarian cancer and in carriers of the gene BRCA1 suggest that hereditary ovarian cancer is genetically heterogeneous.