Abstract P3-02-09: Do radiographic features influence the decision to order a breast MRI? A prospective cohort study

Approximately 75% of the tumors from breast cancer patients express the estrogen receptor (ER) at diagnosis. Since patients with ER-positive tumors respond to endocrine therapy, determination of the ER status of a patient has important consequences for treatment decision making. The current standard practice to assess ER status is by using immunohistochemical staining of a tumor biopsy. However, the ability to collect serial tumor biopsies during treatment to determine a patient's response to endocrine therapy is limited by the feasibility of performing multiple biopsies. 18F-fluoroestradiol positron emission tomography (FES-PET) is an imaging modality which can measure ER levels based on FES uptake and has been previously utilized to assess patients' response to endocrine therapies. Serial imaging of tumor FES uptake during treatment with the selective ER degrader (SERD) fulvestrant, demonstrated that significant residual FES uptake in tumor lesions was associated with early disease progression in patients with metastatic breast cancer (van Kruchten et al, Cancer Discov2015;5:72-81).RAD1901 is a novel, orally available SERD that binds to both ER mutant and wild type forms leading to ER degradation in preclinical models of breast cancer. A prior clinical study of RAD1901 in healthy postmenopausal women demonstrated decreased FES uptake in the uterus after RAD1901 treatment, further supporting the hypothesis that FES-PET imaging can provide an early indication of target effect...
Source: Cancer Research - Category: Cancer & Oncology Authors: Tags: Poster Session Abstracts Source Type: research