title: Twin delivery after IVF-ET with variable dose letrozole-FSH protocol of lower estradiol in a patient previously treated for breast cancer: a case report.
abstract: OBJECTIVE
  To present a case of twin pregnancy obtained by in vitro fertilization and embryo transfer (IVF-ET) with variable dose letrozole-FSH protocol of lower peak estradiol level, after treatment of carcinoma of the breast.
  
  
  METHODS
  A 34-year-old patient diagnosed with mucinous breast carcinoma undergoing assisted fertilization treatment after breast cancer operation and treatment including controlled ovarian stimulation (COS), oocyte retrieval, IVF, and embryo culture and transfer.
  
  
  RESULTS
  Four oocytes were obtained in three COS procedures in the three IVF cycle. All oocytes were fertilized. In the third cycle, two fresh embryos were transferred, and two healthy girls were born at 37 gestational weeks.
  
  
  CONCLUSIONS
  Variable dose letrozole-FSH protocol can maintain lower peak estradiol levels and reduce estrogen exposure after breast cancer operation and chemotherapy.
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Guang-Zhu
authors.initials: GZ
authors.lastname: Hu
authors.forename: Honglu
authors.initials: H
authors.lastname: Diao
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000628:therapy*; D000328:Adult; D047072:Aromatase Inhibitors / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000628:therapy*; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage*; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007247:Infertility, Female / Q000628:therapy*; D000077289:Letrozole; D008596:Menotropins / Q000008:administration & dosage*; D009570:Nitriles / Q000008:administration & dosage*; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D059285:Pregnancy, Twin; D014230:Triazoles / Q000008:administration & dosage*
chemical_list: D047072:Aromatase Inhibitors; D005300:Fertility Agents, Female; D009570:Nitriles; D014230:Triazoles; D004958:Estradiol; D008596:Menotropins; D000077289:Letrozole; D005640:Follicle Stimulating Hormone