Breast Cancer Research and Treatment

, Volume 126, Issue 1, pp 221–226 | Cite as

Cognitive function in postmenopausal breast cancer patients one year after completing adjuvant endocrine therapy with letrozole and/or tamoxifen in the BIG 1-98 trial

  • Kelly-Anne Phillips
  • Julie Aldridge
  • Karin Ribi
  • Zhuoxin Sun
  • Alastair Thompson
  • Vernon Harvey
  • Beat Thürlimann
  • Fatima Cardoso
  • Olivia Pagani
  • Alan S. Coates
  • Aron Goldhirsch
  • Karen N. Price
  • Richard D. Gelber
  • Jürg BernhardEmail author
Brief Report


Endocrine therapy for breast cancer may affect cognition. The purpose of this study was to examine whether cognitive function improves after cessation of adjuvant endocrine therapy. Change in cognitive function was assessed in 100 postmenopausal breast cancer patients in the BIG 1-98 trial, who were randomized to receive 5 years of adjuvant tamoxifen or letrozole alone or in sequence. Cognitive function was evaluated by computerized tests during the fifth year of trial treatment (Y5) and 1 year after treatment completion (Y6). Cognitive test scores were standardized according to age-specific norms and the change assessed using the Wilcoxon signed-rank test. There was significant improvement in the composite cognitive function score from Y5 to Y6 (median of change = 0.22, effect size = 0.53, P < 0.0001). This improvement was consistent in women taking either tamoxifen or letrozole at Y5 (P = 0.0006 and P = 0.0002, respectively). For postmenopausal patients who received either adjuvant letrozole or tamoxifen alone or in sequence, cognitive function improved after cessation of treatment.


Cognitive function Breast cancer Aromatase inhibitor Tamoxifen Letrozole Quality of life 



We thank the patients who participated in this trial, collaborators, and funding sources. Acknowledgment for respective individuals involved in the various groups is given in the Appendix. This work was supported by Novartis and coordinated by IBCSG. Support for the IBCSG: Swedish Cancer Society; The Cancer Council Australia; Australian New Zealand Breast Cancer Trials Group; Frontier Science and Technology Research Foundation; Swiss Group for Clinical Cancer Research (SAKK); National Cancer Institute at the National Institutes of Health (Grant number CA-75362); Cancer Research Switzerland/Oncosuisse; and the Foundation for Clinical Cancer Research of Eastern Switzerland (OSKK);The Cancer Council Victoria, Dr. John Colebatch Clinical Research Fellowship (to K.A.P).

Conflict of interest

Financial disclosures: The substudy was funded by Novartis. Novartis contracted with the International Breast Cancer Study Group (IBCSG) for provision of services related to the conduct and management of the trial. Dr. Thürlimann owns stock in Novartis; Dr. Cardoso has received consulting and/or lecture fees from Novartis, Dr. Thompson and Dr. Goldhirsch have received honoraria from Novartis. The remaining authors have no conflicts to report.


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Copyright information

© Springer Science+Business Media, LLC. 2010

Authors and Affiliations

  • Kelly-Anne Phillips
    • 1
  • Julie Aldridge
    • 2
  • Karin Ribi
    • 3
  • Zhuoxin Sun
    • 2
  • Alastair Thompson
    • 4
  • Vernon Harvey
    • 5
    • 6
  • Beat Thürlimann
    • 7
    • 8
  • Fatima Cardoso
    • 9
  • Olivia Pagani
    • 8
    • 10
  • Alan S. Coates
    • 11
    • 12
  • Aron Goldhirsch
    • 13
    • 14
  • Karen N. Price
    • 15
  • Richard D. Gelber
    • 16
  • Jürg Bernhard
    • 17
    • 18
    Email author
  1. 1.Peter MacCallum Cancer CentreThe University of MelbourneMelbourneAustralia
  2. 2.IBCSG Statistical CenterDana-Farber Cancer InstituteBostonUSA
  3. 3.IBCSG Coordinating CenterBernSwitzerland
  4. 4.Ninewells HospitalUniversity of DundeeDundeeScotland, UK
  5. 5.Auckland City HospitalAucklandNew Zealand
  6. 6.Australian New Zealand Breast Cancer Trials GroupNewcastleAustralia
  7. 7.Breast CenterKantonsspitalSt. GallenSwitzerland
  8. 8.Swiss Group for Clinical Cancer Research (SAKK)BernSwitzerland
  9. 9.Department of Medical OncologyJules Bordet InstituteBrusselsBelgium
  10. 10.Oncology Institute of Southern SwitzerlandOspedale ItalianoLuganoSwitzerland
  11. 11.International Breast Cancer Study GroupBernSwitzerland
  12. 12.University of SydneySydneyAustralia
  13. 13.Department of MedicineEuropean Institute of OncologyMilanItaly
  14. 14.Oncology Institute of Southern SwitzerlandBellinzonaSwitzerland
  15. 15.IBCSG Statistical Center, Frontier Science and Technology Research FoundationDana-Farber Cancer InstituteBostonUSA
  16. 16.IBCSG Statistical Center, Frontier Science and Technology Research FoundationDana-Farber Cancer InstituteBostonUSA
  17. 17.IBCSG Coordinating CenterBernSwitzerland
  18. 18.Department of Medical OncologyInselspital, Bern University HospitalBernSwitzerland

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