18F-FES PET/CT in invasive lobular breast cancer: assessment of axillary lymph node metastasis.

Abstract

Estrogen receptor (ER) is highly expressed in approximately 95% of invasive lobular breast cancer (ILC) and represents a key target for endocrine therapy. ¹⁸F-fluoroestradiol (¹⁸F-FES), a radiolabeled estrogen analog, specifically binds to ER and enables real-time, non-invasive, and whole-body evaluation of ER functional status, providing intuitive visualization of the spatial and temporal heterogeneity of ER expression. ¹⁸F-FES PET/CT sensitively detect primary tumor and distant metastases and accurately identifies axillary lymph node involvement in ILC. Therefore, ¹⁸F-FES PET/CT can serve as a valuable diagnostic tool that can guide the selection of appropriate therapeutic strategies for patients with ILC.