Low Dose Exemestane vs Low Dose Tamoxifen in Post-menopausal Women at High Risk for Breast Cancer.

This is a multicenter, randomized, double blind phase II trial. Eligible patients will be randomized in a 1:1 ratio to: ARM 1: BabyEXE Arm, 25 mg eod, typically every odd day of the monthly calendar for 12 monthsor unless progression, SAE, medical decision, patient withdrawal occur. ARM 2: BabyTAM Arm, 10 mg eod, typically every odd day of the monthly calendar for 12 months or unless progression, SAE, medical decision, patient withdrawal occur. Blinding will be guaranteed by over-encapsulation of active tablet agents with an AA capsule in a 6-month bottle. In both arms, treatment should begin within 30 days from randomization. Exemstane and Tamoxifen will be provided for free by the Study Sponsor. After study completion, participants will be unblinded and treated according to local guidelines. Clinical visit will be performed every 6 months (±14 days) with physical examination vital signs and weight and girth measurement, ECOG PS, MENQOL questionnaire (0, 6, 12 months), review of self-reported compliance, concomitant medications, AEs assessment, and physical exam. Telephone/video contact may be allowed at 3 and 9 months, whereas baseline, 6 months and 12 months visits are necessary for blood collection and biomarker assessment. Blood serum for centralized storage at IEO, Milan, Italy, will be collected at different time points.