Disease-free survival does not differ according to fertility preservation technique for young women with breast cancer

To study whether fertility preservation strategies using ovarian stimulation or without using it impact long-term disease-free survival of patients with breast cancer. Retrospective bicentric cohort study. Two university hospitals. In this study, 740 women with breast cancer, aged 18–43 years, who received primary fertility preservation between 2013 and 2019 after a diagnosis of localized breast cancer were included. Overall, 328 patients underwent at least 1 ovarian stimulation cycle (STIM group) and 412 had a technique without hormonal administration (no STIM group). Disease-free survival and overall survival up to May 2021 were compared between the 2 groups by log-rank test. Cox proportional-hazard regression model was used for multivariable analyses. Out of the 740 women who underwent fertility preservation, follow-up data were available for 269 women in the STIM group (82%) and 330 (80%) in the no STIM group. Kaplan-Meier estimates of disease-free survival at 4 years were 87.9% (82.8%–92.2%) and 83.1% (78.4%–87.3%) in the STIM and no STIM groups, respectively. After adjustment on prognostic parameters, no significant difference in breast cancer recurrence rate was observed between the STIM and no STIM groups (hazard ratios, 0.83 [0.64–1.08]). Kaplan-Meier estimate of overall survival at 4 years was 97.6% (95.3%–99.2%) and 93.6% (90.9%–95.9%) in the STIM and no STIM groups, respectively. Overall survival was higher in the STIM group than no STIM group (log-rank test). After adjustment on prognostic parameters, the risk of death remained significantly lower in the STIM group (Hazard Ratio, 0.55 [0.35–0.85]). In our cohort, STIM for fertility preservation in breast cancer did not significantly impact disease-free survival but was associated with higher overall survival. The disease-free survival and overall survival of young patients with breast cancer were not impacted by fertility preservation techniques irrespective of the timing of chemotherapy (neoadjuvant or adjuvant) and the use of ovarian stimulation. Nevertheless, because death and recurrence were rare events, these results should be taken with caution. El periodo libre de enfermedad no difiere según la técnica de preservación de la fertilidad en mujeres jóvenes con cáncer de mama. Estudiar si las estrategias de preservación de la fertilidad con estimulación ovárica o sin ella influyen en la supervivencia sin enfermedad a largo plazo de las pacientes con cáncer de mama. Estudio retrospectivo de