The aim of this prospective cohort study is to evaluate the modifications of the biological hemostatic profile associated with the use of endocrine therapy in women with breast cancer (tamoxifen or aromatase inhibitors).

In this cohort study, women with breast cancer and an indication for endocrine therapy will be prospectively enrolled. At the 1st visit (before the start of endocrine therapy (tamoxifen or aromatase inhibitor)) and at the 2nd visit (at ~3 months after the start of treatment), demographical / clinical data and blood samples will be collected. We will evaluate the hemostatic biological profiles associated with the use of endocrine therapy by comparing hemostatic biomarkers before and during its use.

Inclusion Criteria: adult women with a diagnosis of non-metastatic breast cancer and an indication for adjuvant endocrine therapy

Exclusion Criteria:

• lack of consent
• planned chemotherapy
• personal history of venous thromboembolism
• ongoing anticoagulant treatment

Women with a new diagnosis of non-metastatic breast cancer and a planned adjuvant endocrine therapy.