18F FES-PET/MRI for Tailoring Treatment of Luminal a and Lobular Breast Cancer

Study hypothesis is that combining the advantages of hybrid PET/MRI and the high sensitivity/specificity of 16-alpha-18F-fluoro-17-beta-estradiol(FES), a radiolabeled form of estrogen binding to functionally active ER, the investigators could obtain a reliable, non-invasive, operator-independent, one-stage imaging method for staging LumA and ER-positive Lobular tumours.

This is a single-centre prospective cohort study where patients with LumA and ER-positive Lob will be enrolled in 4 cohorts undergoing: primary surgery; induction endocrine therapy; neoadjuvant chemotherapy; systemic therapy for metastatic disease. For the purpose of the study an additional FES PET/MRI exam will be performed at baseline for local and systemic staging and a second exam after systemic therapy. Correlations between FES PET/MRI parameters and pathology, gene expression and FDG PET parameters, when available, will be investigated. Aim 1: Evaluating the performance of FES PET/MRI in axillary staging compared with axillary surgery. Aim 2: Evaluating potential correlations between changes in FES uptake and changes in proliferation index after 3 weeks of endocrine therapy before surgery. Aim 3: Evaluating the performance of FES PET/MRI in staging of patients undergoing systemic therapy in comparison with standard imaging. Additionally, biological determinants of tumor heterogeneity will be investigated.