O-084 Fertility outcomes several years after urgent fertility preservation (FP) for breast cancer

Abstract

Abstract Study question What are the fertility outcomes of women who tried to conceive after breast cancer treatment and FP? Summary answer Three to-ten years after FP for breast cancer, less than half of patients tried to conceive but 39% of them had a child, mainly spontaneously. What is known already Breast cancer is the most common cancer in women of childbearing age. Because of the gonadal toxicity of treatments and temporary contraindication to pregnancy, fertility after cancer treatment is often impaired. Different FP techniques can be offered. Although it is well established that pregnancy in breast cancer survivors is safe, little is known on the incidence of pregnancies after breast cancer treatments in women having undergone FP, the way those patients conceived and outcomes. Study design, size, duration This is a retrospective observational, bicentric cohort study. All patients having undergone FP before breast cancer treatment (oocyte and/or embryo vitrification after controlled ovarian stimulation (COS) or in vitro maturation and/or ovarian tissue cryopreservation) between January 1, 2013 and July 31, 2019 were included (n = 844). Patients for whom data on post-cancer pregnancy attempt was missing (n = 195) were excluded from the analysis of pregnancies.The cut-off date was March 1, 2022. Participants/materials, setting, methods For women who got pregnant, the time to conception was calculated between the 1st FP consultation (CS1) and the day of the estimated conception. For those who did not conceived, we considered the time between the CS1 and the cut-off date or the date of patient’s death. Cumulative incidences of pregnancy and live birth were calculated. A logistic regression Cox model was performed to study the predictive factors of pregnancy and live birth. Main results and the role of chance Among the 649 patients with available data on post-cancer pregnancy attempt, 255 (39.3%) tried to conceive. Overall, 135 (52.9%) of them achieved a pregnancy, mainly spontaneously (79.3%), and 99 (38.8%) reported a live birth. At the CS1, 76.3% of women were in couple and 42.3% already had at least a child. The mean age at CS1 was 32±4.2 years. Invasive ductal carcinoma was the diagnosis in 95.8% of women and 45.7% had COS for FP. In our cohort, 48 months after CS1, the cumulative incidence of pregnancy was 33.1% (CI95% [27.6-37.9]). After adjustment on age, parity, type of chemotherapy and hormonotherapy, only multiparity at diagnosis and absence of chemotherapy were found to be positive predictive factors of pregnancy after cancer. Only multiparity was found to be negatively associated with live birth (RR0.47 [0.33-0.67]). Of the 793 patients who vitrified oocytes/embryos, 68 reused them (26.6% of the patients who tried to conceive) and obtained 8 live births. Women using their cryopreserved biological material were older at CS1, had lower ovarian reserve parameters and had vitrified embryos. Ovarian reserve parameters and number of cryopreserved oocytes were higher while age at CS1 was lower in patients reporting a live birth after oocyte/embryo thawing. Limitations, reasons for caution Due to the retrospective nature of the study, some data is missing. Even if the median follow-up is more than 4 years, a longer follow-up is necessary Wider implications of the findings Although pregnancy rates after breast cancer are reduced, most of conceptions are achieved spontaneously. Our findings provide useful information to advise women on the different techniques of FP, their efficacy and safety. Trial registration number Not applicable