title: Comparative efficacy study of 5-year letrozole or anastrozole in postmenopausal hormone receptor-positive early breast cancer.
abstract: OBJECTIVE
  To compare the efficacy of adjuvant anastrozole and letrozole in hormone receptor-positive postmenopausal patients with early breast cancer.
  
  
  METHODS
  A total of 569 hormone receptor-positive postmenopausal early breast cancer patients were included and analyzed in this study. Of them 238 were taking adjuvant anastrozole and 331 adjuvant letrozole. Demographic and medical data including age, menopausal status, weight, height, treatment history and comorbid diseases were collected from their medical charts.
  
  
  RESULTS
  In both anastrozole and letrozole users, the baseline clinicopathologic characteristics and the treatment history with radiotherapy and chemotherapy were similar. The median patient follow-up was 26.4 months. In the anastrozole arm disease free survival (DFS) was 94.9, 81.3 and 66.0%, whereas in the letrozole arm DFS was 90.6, 78.7 and 68.5% in the first, third and fifth years, respectively (p=0.25). Median overall survival (OS) could not be reached due to the low number of events in both arms. Three-year survival rate in the anastrozole arm was 98.8%, whereas in the letrozole arm it was 96.7% (p = 0.20).
  
  
  CONCLUSIONS
  This study showed that both letrozole and anastrozole have similar effects on DFS and OS in the adjuvant hormonal treatment of postmenopausal hormone receptor-positive breast cancer. We believe that this retrospective study is the first to directly compare the efficacy of letrozole and anastrozole.
authors.affiliation: Ankara Numune Education and Research Hospital, Department of Medical Oncology, Ankara, Turkey.
authors.forename: M A N
authors.initials: MA
authors.lastname: Sendur
authors.forename: S
authors.initials: S
authors.lastname: Aksoy
authors.forename: N
authors.initials: N
authors.lastname: Zengin
authors.forename: K
authors.initials: K
authors.lastname: Altundag
mesh_terms: D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage* / Q000009:adverse effects; D047072:Aromatase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D000077289:Letrozole; D008408:Mastectomy; D008875:Middle Aged; D009570:Nitriles / Q000008:administration & dosage* / Q000009:adverse effects; D017698:Postmenopause; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014230:Triazoles / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D014408:Biomarkers, Tumor; D000077289:Letrozole; D009570:Nitriles; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D014230:Triazoles; C508053:ERBB2 protein, human