title: Utilization rates and results of long-term embryo cryopreservation before gonadotoxic treatment.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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%.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Pôle de Recherche en Gynécologie, Institut de Recherche Expérimentale et Clinique (IREC) and Cliniques Universitaires Saint-Luc, Gynecology Department, Université Catholique de Louvain, Avenue Mounier 52 bte B1.52.02, B-1200, Woluwe-Saint-Lambert, Brussels, Belgium, marie-madeleine.dolmans@uclouvain.be.
authors.forename: M M
authors.initials: MM
authors.lastname: Dolmans
authors.forename: S
authors.initials: S
authors.lastname: Hollanders de Ouderaen
authors.forename: D
authors.initials: D
authors.lastname: Demylle
authors.forename: C
authors.initials: C
authors.lastname: Pirard
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000502:physiology; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D059247:Fertility Preservation / Q000379:methods* / Q000706:statistics & numerical data; D005307:Fertilization in Vitro / Q000379:methods / Q000706:statistics & numerical data*; D006801:Humans; D009369:Neoplasms / Q000628:therapy; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D012189:Retrospective Studies; D055815:Young Adult