title: Is letrozole needed for controlled ovarian stimulation in patients with estrogen receptor-positive breast cancer?
abstract: OBJECTIVE
  To assess the advantages and disadvantages of using letrozole for controlled ovarian stimulation (COH) in young patients with estrogen receptor-positive (ER+) breast cancer, wishing to cryopreserve oocytes.
  
  
  METHODS
  Retrospective cohort analysis.
  
  
  METHODS
  Sixteen Italian units for reproductive medicine and in vitro fertilization.
  
  
  METHODS
  Data of 50 ER+ breast cancer patients undergoing COH to cryopreserve oocytes before gonadotoxic chemotherapy with a letrozole plus gonadotropins (Le+Gn) protocol were compared with those of 25 young women with ER- breast cancer, submitted to COH using a protocol with gonadotropins alone (Gn-only).
  
  
  RESULTS
  The Le+Gn protocol implied a significantly lower total Gn consumption and allowed to maintain significantly lower circulating E2 levels at all checkpoints throughout stimulation (peak E2 value 446 ± 357 versus 1553 ± 908 pg/ml, respectively; p = 0.001). On the other side, the Le+Gn protocol allowed a significantly lower yield of oocytes available for cryostorage (6.6 ± 3.5 versus 8 ± 5, respectively; p = 0.038).
  
  
  CONCLUSIONS
  In breast cancer patients, the association of letrozole to Gn significantly reduces the number of oocytes available for cryostorage in comparison with the use of Gn alone. On the other side, it is associated with significantly lower E2 levels during the whole stimulation cycle, a safety issue that has been traditionally considered advantageous in case of ER+ cancers.
authors.affiliation: Phisiopathology of Reproduction and IVF Unit, Department of Surgical Sciences, S. Anna Hospital, University of Torino , Torino , Italy .
authors.forename: A
authors.initials: A
authors.lastname: Revelli
authors.forename: E
authors.initials: E
authors.lastname: Porcu
authors.forename: P E
authors.initials: PE
authors.lastname: Levi Setti
authors.forename: L
authors.initials: L
authors.lastname: Delle Piane
authors.forename: D F
authors.initials: DF
authors.lastname: Merlo
authors.forename: P
authors.initials: P
authors.lastname: Anserini
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D047072:Aromatase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D015331:Cohort Studies; D015925:Cryopreservation; D004958:Estradiol / Q000097:blood; D005260:Female; D059247:Fertility Preservation / Q000009:adverse effects; D006062:Gonadotropins / Q000627:therapeutic use; D006801:Humans; D007558:Italy; D000077289:Letrozole; D009363:Neoplasm Proteins / Q000819:agonists / Q000378:metabolism*; D009570:Nitriles / Q000009:adverse effects / Q000627:therapeutic use*; D054315:Oocyte Retrieval; D009865:Oocytes; D009866:Oogenesis / Q000187:drug effects; D010062:Ovulation Induction; D011960:Receptors, Estrogen / Q000819:agonists / Q000378:metabolism*; D012189:Retrospective Studies; D014230:Triazoles / Q000009:adverse effects / Q000627:therapeutic use*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D006062:Gonadotropins; D009363:Neoplasm Proteins; D009570:Nitriles; D011960:Receptors, Estrogen; D014230:Triazoles; D004958:Estradiol; D000077289:Letrozole