OBJECTIVES:~Primary:~* To evaluate and compare the changes in cognitive function over one year in premenopausal breast cancer patients who receive adjuvant tamoxifen (T) alone against those receive adjuvant tamoxifen (T+OFS) or exemestane (E+OFS) with ovarian function suppression (OFS).~OUTLINE: This is a multicenter study.~Objective cognitive function was measured with the CogState computerized test battery. The CogState battery consists of seven tasks: Detection, Identification, Monitoring, Memory, Learning, International Shopping List Task (ISLT), and ISLT-Delayed Recall. Performance speed is measured for the Detection, Identification and Monitoring tasks and performance accuracy is measured for the Memory, Learning, ISLT, and ISLT-Delayed Recall. Measures of performance speed are normalized using measures of performance accuracy (%) are normalized using arcsine transformation. The main outcome measure is a composite score which is the average of these task scores (after transformation and standardization by age-specific norms). Patients complete these assessments at baseline (i.e. before start of protocol hormonal therapy) and approximately one year after randomization to the parent IBCSG 24-02 (SOFT) study.~Data were collected separately for the T+OFS and E+OFS participants in the parent study, IBCSG 24-02 (SOFT). The sample size for this Co-SOFT substudy was small, so the analysis plan was revised to pre-specify collective analysis for all patients receiving OFS.
RATIONALE: Learning about the long-term effects of adjuvant tamoxifen (T), adjuvant tamoxifen with ovarian function suppression (T+OFS), and exemestane with ovarian function suppression (E+ OFS) on brain function may help doctors plan cancer treatment.~PURPOSE: This study is looking at brain function in premenopausal women who are receiving adjuvant tamoxifen (T) alone against those receive adjuvant tamoxifen (T+OFS) or exemestane (E+OFS) with ovarian function suppression (OFS) for early-stage breast cancer on clinical trial IBCSG-2402.