The prevalence of hereditary breast/ovarian cancer risk in patients with a history of breast or ovarian cancer in Japanese subjects.

Aim: Women at high risk for hereditary breast/ovarian cancer require specific management strategies for cancer prevention and early detection. The authors sought to determine the prevalence of family histories suggestive of a hereditary breast/ovarian cancer syndrome in patients with a personal history of breast or ovarian cancer in Japanese women.
Methods: Family history (first- and second-degree relatives) data were collected by a self-administered questionnaire for women with a history of breast or ovarian cancer in six major cancer treating hospitals in Niigata prefecture, Japan.
Results: Data were obtained from 1463 women: 626 women with a history of breast cancer, 289 women with a history of ovarian cancer and 548 women without a history of any cancer as controls. Women with a family history of breast and/or ovarian cancer had OR of breast cancer of 2.3 (95% confidential interval [CI] 1.5-3.7) and ovarian cancer of 2.2 (95% CI 1.3-3.8). The risk was higher when the proband was younger or when two or more relatives were affected. Among women with a history of breast or ovarian cancer, 7.5% met the criteria for a 10% risk of a BRCA1 or BRCA2 mutation according to the Myriad model.
Conclusion: Obtaining a detailed breast and ovarian cancer family history and the application of the Myriad model is useful for identifying women at an elevated genetic risk of breast and ovarian cancer. The estimation for the prevalence of hereditary breast/ovarian cancer syndrome has significant implications for a patient's management, as well as for the capacity for risk assessment and testing.