BRCA1/2 genetic testing to use PARP inhibitor for breast cancer has a possibility of the “secondary finding” among the younger nonaffected family members of the patient, which turns them into at-risk for hereditary breast cancer. Proper understanding of the background of the hereditary cancer is now required for appropriate acceptance of the risk. Therefore, we investigated the level of knowledge and attitudes of younger women on hereditary breast cancer in Japan. Study subject was Japanese university women between 20 and 30 years of age, without medical history of breast cancer. We conducted the anonymous self-answering questionnaire to them. We received responses from 353 women. The levels of knowledge, awareness, and interest were relatively high. Women with a family history of breast cancer were less likely to undergo testing than women without (92.8% vs. 74.5%, p < 0.001). The rates of positive response toward risk-reducing mastectomy (RRM) and risk-reducing salpingo-oophorectomy (RRSO) was significantly high for medical majors compared with that for other majors (RRM: medical 71.6% vs. science 54.5% vs. humanities 53.8%, p = 0.008, RRSO: 35.4% vs. 36.3% vs. 48.4%, p = 0.027). Approximately half of respondents answered that they would hesitate to get married (45.3%) or to have children (55.4%), if they were a BRCA1/2 mutation carrier. The results may help to establish the methods for supporting the decision-making for reproduction of younger women who are unexpectedly labeled as being at-risk for HBOC.

BRCA1 / 2使用PARP抑制剂治疗乳腺癌的基因检测可能会在年轻的未受影响患者家庭成员中“继发发现”，这使他们成为遗传性乳腺癌的高危人群。为了适当地接受风险，现在需要对遗传性癌症的背景有正确的了解。因此，我们调查了日本年轻女性对遗传性乳腺癌的知识水平和态度。研究对象是日本大学女性，年龄在20至30岁之间，没有乳腺癌的病史。我们向他们进行了匿名的自我回答问卷。我们收到了353名妇女的回复。知识，意识和兴趣水平较高。有乳腺癌家族史的女性比没有乳腺癌的女性接受测试的可能性较小（92。p  <0.001）。与其他专业相比，医学专业对降低风险的乳腺切除术（RRM）和降低风险的输卵管卵巢切除术（RRSO）的阳性反应率显着较高（RRM：医学专业为71.6％，科学为54.5％，人文为53.8 ％，p  ＝ 0.008，RRSO：35.4％对36.3％对48.4％，p  ＝ 0.027）。大约一半的受访者回答说，如果他们是BRCA1 / 2突变携带者，他们会犹豫结婚（45.3％）还是生孩子（55.4％）。结果可能有助于建立支持决策的方法，这些决策被意外标记为HBOC的高危女性。