title: Serum estradiol should be monitored not only during the peri-menopausal period but also the post-menopausal period at the time of aromatase inhibitor administration.
abstract: BACKGROUND
  Aromatase inhibitor (AI) therapy is being extensively used as postoperative adjuvant therapy in patients with hormone receptor-positive postmenopausal breast cancer. On the other hand, it has been reported that ovarian function was restored when AI was administered to patients who had undergone chemical menopause with chemotherapy or tamoxifen. However, there have been no reports of comprehensive monitoring of estradiol (E2) in breast cancer patients with ordinary menopause who were being administered AI.
  
  
  METHODS
  Beginning in March 2008, regular monitoring of the serum levels of E2, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) was performed for 66 postmenopausal breast cancer patients who had been started on AI therapy. For this study, we chose anastrozole as the AI. The assays of those hormones were outsourced to a commercial clinical laboratory.
  
  
  RESULTS
  In 4 of the 66 patients the serum E2 level was decreased at 3 months but had then increased at 6 months, while in 2 other patients E2 was decreased at both 3 and 6 months but had increased at 9 months.
  
  
  CONCLUSIONS
  The results indicate that, in some breast cancer patients with ordinary menopause, E2 rebounds following AI therapy. In the future, E2 monitoring should be performed for a larger number of patients being administered AI therapy.
  
  
  BACKGROUND
  Our trial registration number is 19-11-1211.
authors.affiliation: Department of Oncological and Regenerative Surgery, Institute of Health Biosciences, The University of Tokushima, Tokushima, Japan. tnagao@clin.med.tokushima-u.ac.jp
authors.forename: Taeko
authors.initials: T
authors.lastname: Nagao
authors.forename: Misako
authors.initials: M
authors.lastname: Kira
authors.forename: Masako
authors.initials: M
authors.lastname: Takahashi
authors.forename: Junko
authors.initials: J
authors.lastname: Honda
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hirose
authors.forename: Akira
authors.initials: A
authors.lastname: Tangoku
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Zembutsu
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Sasa
mesh_terms: D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D047072:Aromatase Inhibitors / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant; D004958:Estradiol / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D009570:Nitriles / Q000627:therapeutic use*; D047648:Perimenopause; D017698:Postmenopause; D014230:Triazoles / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D009570:Nitriles; D014230:Triazoles; D000077384:Anastrozole; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone