RATIONALE: Studying cognitive function, such as thinking, attention, concentration, and memory, in postmenopausal women receiving hormone therapy for breast cancer may help improve quality of life and the ability to plan treatment for cancer.

PURPOSE: This phase III trial is studying 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.

DISEASE CHARACTERISTICS:

• Enrolled in protocol IBCSG-1-98

  • Must be in the fifth year of study treatment (i.e., still receiving tamoxifen or letrozole)

• No breast cancer recurrence or second malignancy

• Patients who received 2-4½ years of tamoxifen and have chosen to switch to letrozole to complete 5 years of treatment on protocol IBCSG-1-98 are not eligible

• Hormone receptor status

  • Estrogen receptor- and/or progesterone receptor-positive tumor

PATIENT CHARACTERISTICS:

• Female
• Postmenopausal

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No concurrent hormone replacement therapy