With the advancement of treatment technology, more and more breast cancer patients have been diagnosed and treated in a timely and effective manner, and their long-term survival rate has increased significantly. The number of young breast cancer patients in China is gradually increasing and their childbearing age is generally delayed, so the fertility needs of these patients have become more urgent. However, various treatments, mainly chemotherapy, may have an impact on patients’ fertility, especially chemotherapy has a direct effect on ovarian function. The incidence of permanent amenorrhea after systemic therapy has been reported in the foreign literature to range from 33% to 76%. Therefore, fertility after treatment and the possibility of having children becomes an important issue for young breast cancer patients and clinicians. 1. Can I have children after treatment? During a normal menstrual cycle, there are two significant fluctuations in estrogen levels and one significant increase in progesterone levels. During pregnancy, childbirth and breastfeeding, there are even more hormones involved and the changes are even more complex. This raises a concern that since breast cancer is a tumor closely related to hormone levels and endocrine therapy to antagonize estrogen and progesterone has become a routine and effective treatment, will the changes in hormone levels cause tumor cells to proliferate and even cause breast cancer to recur during the process of reproduction after treatment of breast cancer patients, thus affecting their prognosis? There has been a lot of evidence that amenorrhea after breast cancer treatment has a positive effect on improving the long-term survival of patients. As early as 1988, a study by the International Breast Cancer Research Collaboration noted that the prognosis of patients with estrogen receptor (ER)-positive premenopausal breast cancer who experienced chemotherapy-induced amenorrhea, even temporarily, was significantly improved, while a study published by Swain et al. in 2010 further noted that all patients with early-stage breast cancer who had amenorrhea for more than 6 months after chemotherapy had an improved overall survival rate In 2010, Swain et al. The impact of post-treatment fertility on patient prognosis Several studies suggest that patients who have children after treatment have better long-term survival than those who do not have children at the same age, and that there is at least no negative impact of post-treatment fertility. Possible explanations include: (1) the presence of fetal antigens on the surface of the tumor, with pregnancy acting as a “vaccine”; (2) laboratory studies have shown that high levels of estrogen, on the contrary, can cause apoptosis in ER and progesterone receptor (PR)-positive tumor cells; (3) additional clinical observations have shown that patients who continue to breastfeed after delivery (a type of postpartum continuation) are more likely to have a positive prognosis. patients (a natural way to continue to maintain lower estrogen levels after delivery), the prognosis is even better. It is evident that post-treatment amenorrhea and post-treatment fertility are issues in different directions, not two opposing sides of the same issue, and that post-treatment amenorrhea improves the long-term survival of breast cancer patients, and that resumption of fertility without amenorrhea or after temporary amenorrhea has a positive effect on patient prognosis.