Outcomes of random-start letrozole protocol with PGT-A in women with breast cancer undergoing fertility preservation

Purpose To compare the cycle characteristics and outcomes of random-start-controlled ovarian stimulation (RSCOS) protocols to the outcomes of standard-start-controlled ovarian stimulation (SSCOS) cycles and to report the utility of PGT-A in these cycles. Methods One hundred and seventeen who underwent SSCOS and 39 who underwent RSCOS for oocyte and/or embryo cryopreservation before breast cancer chemotherapy were retrospectively evaluated. Mean number of embryos and blastocyst euploidy rates were the main outcome measures. Results A majority of RSCOS cycles were initiated in the luteal phase (66.6% luteal vs. 33.3% follicular). While the total dose of gonadotropins was significantly higher in the RSCOS (3720.8 ± 1230.0 vs. 2345.1 ± 803.6 IU; P < 0.001), the mean number of mature oocytes and embryos was similar to SSCOS. However, there was a trend for a higher number of mean embryos with luteal start RSCOS (6.9 ± 2.7 in late follicular start vs. 9.4 ± 4.2 in luteal start, P = 0.08). PGT-A was performed in 48% of the cases that underwent embryo cryopreservation in RSCOS (12 women, mean age = 35.3 ± 4.1; 87 blastocysts), revealing a euploidy rate of 36.2 ± 22.3% per patient. This rate was comparable to a 45% aneuploidy rate from similarly aged published data. Of the 7 RSCOS patients who returned for frozen embryo transfer, 5 delivered and one has an ongoing pregnancy, while in SSCOS, 18 out of 40 cycles resulted in live birth. Conclusion Our data suggests that RSCOS fertility preservation cycle outcomes are similar to those with SSCOS and result in age-appropriate euploidy rates.