Case‐based survey: The impact of breast‐cancer treatment on fertility in Japan

Aim To assess the impact of breast‐cancer treatment on fertility. Methods We conducted a retrospective, case‐based survey of treatments administered for infertility and pregnancy outcomes after patients underwent treatment for breast cancer. Surveys were distributed to breast oncology facilities and reproductive endocrinology and infertility (REI) facilities. Results As high as 60% of the pregnancies in women under the age of 35 years occurred spontaneously. Additionally, the fertility rates decreased as age increased (under 35 years of age: 40%, 35–39 years of age: 21%, 40–44 years of age: 10%, respectively). In women who became pregnant after treatment for breast cancer, conception was achieved within 1 to 3 years after beginning to try for pregnancy. Conclusions After treatment for breast cancer, women can expect spontaneous pregnancy, especially if they are under 35 years of age. It is important for patients 35 years of age and older to commence assisted reproductive technology in a timely manner when pursuing fertility after treatment for breast cancer.