Phase II Study of 18F-FFNP Breast PET/MRI in the Assessment of Early Response of Breast Cancer to Presurgical Endocrine Therapy

This clinical trial will investigate an estrogen-regulated parameter as an early measure of endocrine therapy response: progesterone receptor (PR) protein with a progestin-based radioligand, 18F-fluorofuranylnorprogesterone (18F-FFNP). The overall purpose of this research is to test the efficacy of 18F-FFNP PET/MRI for predicting response to presurgical endocrine therapy and to determine the quantitative reliability of 18F-FFNP breast PET/MRI in patients with newly diagnosed ER+/PR+/HER2- primary breast cancer.