Cognitive effects of adjuvant endocrine therapy in older women treated for early-stage breast cancer: a 1-year longitudinal study

Support Care Cancer. 2019 Aug;27(8):3035-3043. doi: 10.1007/s00520-018-4603-5. Epub 2019 Jan 4.


Purpose: Evidence suggests endocrine therapy (ET) for breast cancer (BC) has adverse cognitive effects, but its specific effects on older women are unknown. This is despite the fact that older women are at increased risk of both breast cancer (BC) and cognitive decline relative to younger women. This study prospectively examined the cognitive effects of ET in a cohort of older BC patients. Our primary outcome measure was change in verbal memory, the cognitive domain most consistently affected by estrogen deprivation.

Methods: Forty-two chemotherapy-naïve women age 60+, without dementia and recently diagnosed with hormone receptor-positive BC, completed neuropsychological tests at the time of ET initiation and after 1 year of treatment. Change in age-standardized verbal memory performance was examined using paired t tests. To assess a broader range of potential cognitive effects, we also examined changes in visual memory, processing speed, frontal executive function, and perceptual reasoning.

Results: Participants exhibited significant decline from baseline to 1 year in verbal memory (p = 0.01). This decline was small to moderate in effect size (d = - 0.40). Performance on other domains did not change significantly over the year (all p > 0.05).

Conclusions: Our findings suggest potentially detrimental effects of ET on verbal memory in older women after just 1 year of treatment. Given that ET is prescribed for courses of 5 to 10 years, additional studies examining longer-term effects of treatment in older women are critical.

Keywords: Aged; Breast cancer; Cognition; Endocrine therapy; Verbal memory.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Antineoplastic Agents, Hormonal / adverse effects*
  • Antineoplastic Agents, Hormonal / therapeutic use
  • Aromatase Inhibitors / administration & dosage
  • Aromatase Inhibitors / therapeutic use
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Breast Neoplasms / psychology*
  • Chemotherapy, Adjuvant
  • Cognition / drug effects*
  • Cognitive Dysfunction / chemically induced*
  • Cohort Studies
  • Combined Modality Therapy
  • Executive Function / drug effects
  • Female
  • Humans
  • Longitudinal Studies
  • Memory / drug effects
  • Middle Aged
  • Neoplasm Staging
  • Neuropsychological Tests
  • Prospective Studies
  • Receptors, Estrogen / metabolism
  • Receptors, Progesterone / metabolism
  • Tamoxifen / adverse effects
  • Tamoxifen / therapeutic use


  • Antineoplastic Agents, Hormonal
  • Aromatase Inhibitors
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Tamoxifen