Utilization rates and results of long-term embryo cryopreservation before gonadotoxic treatment

The aim of this study was to evaluate long-term embryo cryopreservation, utilization, and success rate in patients subjected to gonadotoxic treatments in the context of cancer. This is a retrospective study on patients (n = 54) undergoing ovarian stimulation and IVF for fertility preservation between January 1997 and June 2014. Embryos were slow-frozen and stored until the women were cured and able to undergo embryo transfer. Fifty-four women underwent 66 oocyte pick-up procedures in total, and embryos were obtained from 52 of the 54 patients. Four patients died before their frozen embryos could be thawed. Of the remaining 48, 9 women returned to use their embryos, resulting in 6 pregnancies (66 % cumulative pregnancy rate), two of which ended in miscarriage. The live birth rate per patient was thus 44 % (4/9). The true come-back rate, calculated after applicable exclusions, was found to be 23 %. IVF followed by embryo freezing is a widely established technique for fertility preservation, but little has been published on the outcomes in cancer patients. While we found the number of good-quality embryos to be lower than in a normal population, the cumulative live birth rate was similar to that achieved with fresh embryos in non-cancer patients. The utilization rate of this fertility preservation method can be considered high.