Cognitive Function in Postmenopausal Women With Breast Cancer Receiving Hormone Therapy on Clinical Trial IBCSG-1-98

OBJECTIVES: Primary * Compare cognitive function in postmenopausal women with breast cancer who have received 5 years of adjuvant tamoxifen vs letrozole on protocol IBCSG-1-98. Secondary * Compare cognitive function in patients who have received a single hormonal therapy for 5 years vs those who have received that same hormonal therapy for 3 years, having previously received an alternate hormonal therapy for 2 years. * Compare improvement in cognitive function 1 year after cessation of adjuvant hormonal therapy. * Compare changes in cognitive function in patients who have received prior adjuvant chemotherapy vs those who have not received adjuvant chemotherapy. * Assess the relationship between objective and subjective measures of cognitive function, including specific cognitive domains. * Assess the relationship between cognitive function and psychological distress, fatigue, and quality of life. OUTLINE: This is a longitudinal, multicenter study. Patients undergo cognitive function testing and complete self-reported questionnaires regarding cognitive ability, quality of life, fatigue, and psychosocial status during the fifth year of adjuvant hormonal therapy on protocol IBCSG-1-98 and then during the sixth year\* (post randomization on protocol IBCSG-1-98) (i.e., after completion of adjuvant hormonal therapy). NOTE: \*Patients who receive extended letrozole, hormone replacement therapy, or other endocrine therapy beyond 5 years do not undergo the 6-year assessment. PROJECTED ACCRUAL: A total of 148 patients will be accrued for this study.