Perspectives on Preimplantation Genetic Testing for Monogenic Disorders Among Japanese Patients With Hereditary Breast Cancer Undergoing Fertility Preservation: Insights From the First Japanese Survey

Purpose: Preimplantation genetic testing for monogenic disorders (PGT-M) offers BRCA variant carriers the option of preventing hereditary cancer transmission. We investigated the awareness and attitudes toward PGT-M among patients with breast cancer who underwent fertility preservation. Methods: A questionnaire-based survey was administered to 264 patients with breast cancer who were eligible for oocyte or embryo cryopreservation at in vitro fertilization clinics between October 2024 and March 2025. A total of 161 valid responses were analyzed. The survey assessed BRCA testing status, PGT-M awareness, willingness to undergo PGT-M, and opinions on future availability. Results: The uptake rate of BRCA1/2 testing was 53.4%; 14% of the respondents were variant carriers. Only 16.8% had prior awareness of PGT-M, and 47.8% expressed a willingness to use PGT-M if available. Among BRCA-variant carriers, 3.3% reported that they would consider PGT-M, and 75% believed it should be made available upon request. Overall, 68.3% supported information sharing between oncology and fertility providers. Conclusion: These findings highlight the importance of expanding reproductive options and patient awareness of PGT-M in the care of patients with hereditary cancer. Discussions should focus on how best to provide accurate information and enable informed reproductive choices for those at genetic risk.