16α-18F-fluoro-17β-Fluoroestradiol (FES): Clinical Applications for Patients With Breast Cancer

Estrogen receptor (ER) is highly expressed in 70%-80% of breast cancers and plays a central role in prognosis and treatment selection for patients with breast cancer. The gold standard for determining ER status in breast cancer has been pathology; however, tissue samples are invasive to obtain and only provide information on individual lesions. It is increasingly recognized that there is often spatial and temporal heterogeneity of ER status between lesions, which limits our ability to make decisions based on only one or a few tissue samples. Likewise, it is increasingly recognized that ER may be present, but not functional, thus knowledge of the ER status on pathology is not sufficient to determine the role ER plays in oncogenesis in individual patients or to make optimal treatment decisions. 16α-18F-fluoro-17β-Fluoroestradiol (FES) is a radiolabeled form of estrogen that binds to ER and allows non-invasive, whole-body evaluation of functional ER. FES has been shown to correlate with ER immunohistochemistry, successfully demonstrate ER heterogeneity, and provide high diagnostic accuracy for the detection of ER-positive tumors. FES was FDA approved May 20, 2020, as a diagnostic agent for the detection of ER-positive lesions as an adjunct to biopsy in patients with recurrent or metastatic breast cancer. FES has demonstrated sensitive detection of ER-positive malignancy in several anatomic sites, including bone, lymph nodes, and brain. Visualization of liver lesions is hampered by physiologic liver and biliary excretion of FES. Potential clinical applications of FES include selecting appropriate patients for hormonal therapies, assessing ER-status in lesions that are difficult to biopsy, solving clinical dilemmas when there are inconclusive results from other diagnostic studies, systemic staging of ER-positive breast cancers with low metabolic activity and not well visualized by FDG, and selecting optimal dosage for current or novel ER-targeted therapies to abrogate ER function and oncogenesis. FES binding to ER is blocked by selective estrogen receptor modulators, such as tamoxifen, and selective estrogen degraders, such as fulvestrant. Patients will need to be withdrawn from these treatments prior to FES imaging. The aim of this review is to provide an overview of FES PET, how it is performed, potential clinical applications, limitations, and what may be on the horizon for this growing tool for the care of patients with breast cancer.

留言 (0)

沒有登入
gif