Breast Cancer Research and Treatment

, Volume 125, Issue 3, pp 741–749 | Cite as

Anastrozole and letrozole: an investigation and comparison of quality of life and tolerability

  • J. Michael Dixon
  • Lorna Renshaw
  • Carolyn Langridge
  • Oliver E. Young
  • Mary McHugh
  • Linda Williams
  • Juliette Murray
  • E. Jane Macaskill
  • Fiona McCaig
  • Oliver M. Dixon
  • Lesley J. Fallowfield
Clinical trial


Previous studies have demonstrated that both anastrozole and letrozole are well tolerated. Letrozole suppresses estrogen to a greater degree than anastrozole in the serum and breast tumor. Concerns have been raised that greater potency may adversely affect patients’ quality of life (QOL). One hundred eighty-one postmenopausal women with invasive estrogen receptor-positive breast cancers were randomized to receive either 12 weeks of letrozole followed by 12 weeks of anastrozole or the reverse sequence. One hundred and six received immediate adjuvant aromatase inhibitors (AIs) following surgery, and 75 received extended adjuvant therapy. The Functional Assessment of Cancer Therapy Endocrine Subscale (FACT-B-ES) QOL questionnaires were completed to assess QOL on each drug. Additional side-effect profiles were collected. Each patient completed a patient preference form. Twenty-one patients withdrew before study end, 10/179 (5.6%) while taking letrozole and 4/173 (2.3%) while taking anastrozole (P = 0.12). Tamoxifen-naïve patients had a higher mean ES (endocrine symptoms subscale) score at entry versus those having extended therapy (66.0 vs. 61.9; P = 0.001). There was no significant change in FACT-B-ES (overall) scores or ES scores while patients were taking anastrozole or letrozole and no significant differences between drugs. Nearly 80% of patients reported one or more side effects with either agent. No differences in frequency, grade, or range of side effects were seen between drugs. Of 160 patients, 49 (30.6%) preferred letrozole, 57 (35.6%) preferred anastrozole, and 54 (33.8%) had no preference (P = 0.26, Pearson’s Chi-squared test). In conclusion, both AIs are equally well tolerated. There were no significant differences in QOL scores between the two drugs.


Anastrozole Breast cancer Letrozole Quality of life Tamoxifen 



Financial support for medical editorial assistance was provided by Novartis Pharmaceuticals. We thank Maria Soushko, PhD, of Phase Five Communications Inc. for medical editorial assistance with this manuscript. Financial support for this study was provided by Novartis Oncology.

Supplementary material

10549_2010_1091_MOESM1_ESM.ppt (46 kb)
Results from the drug preference questionnaire (online only) (PPT 46 kb)


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Copyright information

© Springer Science+Business Media, LLC. 2010

Authors and Affiliations

  • J. Michael Dixon
    • 1
  • Lorna Renshaw
    • 1
  • Carolyn Langridge
    • 2
  • Oliver E. Young
    • 1
  • Mary McHugh
    • 1
  • Linda Williams
    • 3
  • Juliette Murray
    • 1
  • E. Jane Macaskill
    • 1
  • Fiona McCaig
    • 1
  • Oliver M. Dixon
    • 1
  • Lesley J. Fallowfield
    • 2
  1. 1.Edinburgh Breast UnitWestern General HospitalEdinburghUK
  2. 2.CRUK Sussex Psychosocial Oncology Group, Sussex Health Outcomes Research and Education in Cancer (SHORE-C), Brighton & Sussex Medical SchoolUniversity of SussexFalmerUK
  3. 3.Public Health SciencesUniversity of Edinburgh, Medical SchoolEdinburghScotland, UK

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