Monitoring Symptoms to Help Young Women Take Hormone Therapy for Stage I-III Breast Cancer, ASPEN Study

Inclusion Criteria: * Participants must be female and have Stage I, II, or III hormone receptor positive breast cancer based on clinical or pathologic evaluation * Participants must have been pre- or peri-menopausal at the time of breast cancer diagnosis by satisfying one of the following: * had a menstrual period (by self-report) within the 12 months before breast cancer diagnosis, or * had a serum or plasma estradiol and/or follicle stimulating hormone (FSH) concentration consistent with premenopausal status (based on institutional standards) within the 12 months before breast cancer diagnosis or when checked after breast cancer diagnosis * Participants must have started initial treatment with standard of care oral endocrine therapy (ET) (i.e., tamoxifen, anastrozole, exemestane, or letrozole; within 14 days prior to randomization or be planning to start initial treatment with standard of care oral ET within 14 days after randomization * Participants who currently have ovarian function (estradiol above the postmenopausal range) must be planning to undergo ovarian suppression or ablation concomitantly with oral ET medication, starting before or at the same time as oral ET initiation. Participants with chemotherapy-induced amenorrhea or ovarian failure at time of registration must be planning to start ovarian suppression or ablation if they have recurrence of ovarian function during study participation (circulating estradiol concentration in the premenopausal range or r…