Nationwide survey of Japanese breast oncology and reproductive endocrinology departments about the impact of breast cancer treatment on fertility.

The purpose of this study is to assess the impact of breast cancer treatment on the reproductive potential. We conducted a nationwide survey of breast oncology and reproductive endocrinology and infertility (REI) departments using a questionnaire designed to assess the impact of breast cancer treatment on fertility. We received responses from 312 breast oncology departments (response rate, 31.9%) and 541 REI departments (response rate, 50.9%). The most common method of achieving pregnancy reported by breast oncology departments was natural insemination (69.6%), followed by assisted reproductive technology ( 15.6%) and intrauterine insemination (IUI; 14.8%). The most common method of achieving pregnancy reported by REI departments was conventional in vitro fertilization and/or intracytoplasmic sperm injection (51.0%), followed by natural insemination with or without ovulation induction (40.0%) and IUI (8.0%). The overall pregnancy rate for patients who underwent treatment for infertility at REI departments after breast cancer treatment was 39.0%. Vast patients who experienced breast cancer treatments conceived mainly by natural insemination based on the data from breast oncology departments. On the other hand, 61.0% of the patients who visited REI departments presumably due to infertility by natural insemination did not conceive even by infertility treatments with exclusive knowledge in REI departments.