Clinical outcome of embryo cryopreservation in Japanese breast cancer patients: pregnancy rates after transfer of thawed embryos.

Abstract

To examine pregnancy outcomes after cryopreserved embryo transfer (ET) in breast cancer patients and to investigate the effect of controlled ovarian hyperstimulation (COH) as well as that of aromatase inhibitor (AI) administration and of the random start (RS) ovarian stimulation method. This retrospective study covered 126 patients who underwent embryo cryopreservation between 2010 and 2019. Thirty-one patients underwent frozen embryo transfer (FET), and we examined resulting pregnancy rates (PRs) and live birth rates (LBRs) in those who did and did not undergo COH and in relation to the AI and RS methods. PR and LBR per patient were higher among patients who underwent COH than among those who did not. PR per ET did not differ from that documented for non-cancer infertility patients, after adjustment for age. The PR and LBR did not differ between use and non-use of AI (27.8% vs 35.2%). In addition, there was no significant difference in the PR or LBR between RS and conventional start ovarian stimulation (33.3% vs 30.8%). No prenatal fetal abnormalities were observed in 8 cases (including 5 AI cases and 2 RS cases). This study showed that the outcome of FET after FP was equivalent to that seen in non-cancer patients. Further, neither use of AI nor the RS method influenced LBR. COH including use of AI and the RS method are useful in FP for collecting and freezing many embryos within a short period and for increasing the per patient LBR after cancer treatment.