• Changes in cognitive function over 1 year in premenopausal breast cancer patients who receive adjuvant tamoxifen with or without ovarian function suppression (OFS) [ Designated as safety issue: No ]
  

• The effect of tamoxifen with OFS versus exemestane with OFS on cognitive function over 1 year [ Designated as safety issue: No ]
  
• The effect of tamoxifen alone versus exemestane with OFS on cognitive function over 1 year [ Designated as safety issue: No ]
  
• Comparison of changes in cognitive function over 5 years and 6 years [ Designated as safety issue: No ]
  
• Impact of receiving prior chemotherapy or not on changes in cognitive function [ Designated as safety issue: No ]
  
• The relationship between subjective and objective cognitive function [ Designated as safety issue: No ]
  
• The relationship between cognitive function, psychological distress, fatigue, insomnia, and quality of life [ Designated as safety issue: No ]
  

OBJECTIVES:

Primary:

• To evaluate and compare changes in cognitive function over 1 year in premenopausal breast cancer patients who receive adjuvant tamoxifen with or without ovarian function suppression (OFS).

Secondary:

• To compare the effect of tamoxifen with OFS versus exemestane with OFS on cognitive function over 1 year.
• To compare the effect of tamoxifen alone versus exemestane with OFS on cognitive function over 1 year.
• To evaluate and compare changes in cognitive function over 5 years and 6 years between the 3 treatment groups (pending funding becoming available for the year 5 and 6 measures) on clinical trial IBCSG-2402.
• To explore the impact of receiving or not receiving prior chemotherapy on changes in cognitive function.
• To explore the relationship between subjective and objective cognitive function.
• To explore the relationship between cognitive function, psychological distress, fatigue, insomnia, and quality of life.

OUTLINE: This is a multicenter study.

Patients undergo objective cognitive function assessment over 20-25 minutes, using the CogState computerized test battery, which consists of five tasks that measure the speed of psychomotor function, visual attention, working memory and the accuracy of working memory, learning and memory and executive function (all non-verbal). They undergo subjective cognitive function assessment, using the Cognitive Failures Questionnaire (CFQ), a 25-item self-report measure that assesses a person's failures in memory, perception, and motor function over the past 6 months. Patients also complete General Health Questionnaire -12 (measuring psychologic distress), Brief Fatigue Inventory, NCI Common Terminology Criteria for Adverse Events, and a patient-rated linear analogue self-assessment (LASA) scale measuring insomnia. Patients complete these assessments at baseline (after registration to clinical trial IBCSG-2402, but before beginning protocol therapy) and at 1, 5, and 6 years after randomization on IBCSG-2402.

Relevant clinical factors, such as age, adjuvant chemotherapy, co-morbidity and concomitant medications are assessed. In addition, language, education, psychiatric and neurological history, alcohol consumption and right/left handedness are also assessed.