Fertility outcomes several years after urgent fertility preservation for patients with breast cancer

Abstract

Objective: To study the fertility outcomes of women who tried to conceive after breast cancer (BC) treatment and fertility preservation.

Design: Retrospective observational, bicentric cohort study.

Setting: University hospital.

Patients: Patients with BC.

Intervention: All patients who had undergone fertility preservation before BC treatment between January 2013 and July 2019 were included (n = 844). The endpoint date was March 1, 2022. Patients with missing data on pregnancy attempts after a cancer diagnosis (n = 195) were excluded from the pregnancy analysis.

Main outcome measures: Cumulative incidences of pregnancy and live birth (LB) were calculated. For women who became pregnant, the time to conception was calculated between the first fertility preservation consultation and the estimated day of conception. For those who did not conceive, we considered the time between the first fertility preservation consultation and the endpoint date, or the date of patient death. A Cox regression model was used to study the predictive factors for pregnancy and LB.

Results: Among the 649 patients with available data on pregnancy attempts after BC diagnosis, 255 (39.3% [35.5-43.2]) tried to conceive (median follow-up of 6.5 years). Overall, 135 (52.9% [46.6-59.2]) of these patients achieved a pregnancy, mainly through unassisted conception (79.3% [72.8-84.8]), and 99 reported an LB (representing 38.8% of patients who attempted conception). In our cohort, 48 months after the first fertility preservation consultation, the cumulative incidence of pregnancy was 33.1% ([27.6-37.9]). After adjustment for age, parity, type of chemotherapy administration, and endocrine therapy, only multiparity at diagnosis and absence of chemotherapy were positive predictive factors of pregnancy after cancer. Of the 793 patients who had vitrified oocytes and embryos, 68 used them (27% [21.3-32.5] of the patients who tried to conceive), resulting in 8 LBs (11.8% [5.2-21.9]). Women who used their cryopreserved oocytes and embryos were older at the first consultation of fertility preservation (hazard ratio 1.71 [1.42-2.21]), and chose more often to vitrify embryos (hazard ratio 1.76 [1.28-2.23]).

Conclusion: Although pregnancy rates after fertility preservation for patients with BC are low, most conceptions are achieved without medical assistance. Our findings provide useful information to advise women on the different techniques of fertility preservation, their efficacy, and safety, as well as the relatively high chances of unassisted conception.

Keywords: Breast cancer; fertility preservation; infertility; live birth; pregnancy.