The role of intestinal microbiota in breast cancer treatment with hormone therapy: a pathway to new therapeutic options

Interventions: No interventions Observational study Primary outcome(s): The primary endpoint is microbiota composition before and during (after 6 – 12 weeks) systemic hormone therapy in relation to systemic estrogen and endoxifen levels in respectively the cohort treated with aromatase inhibitors and tamoxifen. Study Design: Open (masking not used), N/A , unknown, Parallel