Abstract PS3-06: Fluoroestradiol F18 positron emission tomography diagnostic performance to characterize estrogen receptor status in breast cancer

Background Estrogen receptor (ER) status by immunohistochemistry (IHC) of breast cancer tissue is currently used to direct endocrine therapy. Fluoroestradiol F18 (18F-FES) is a noninvasive method to determine the presence and ligand-binding function of the ER in metastatic breast cancer lesions throughout the body. Concordance of imaging and tissue assays should be established for 18F-FES PET to be an alternative or complement to tissue biopsy for metastatic lesions. Objective We conducted a meta-analysis of published results comparing 18F-FES PET and tissue assays of ER status in patients with breast cancer. Method PubMed and EMBASE were searched for English-language manuscripts with at least 10 patients and low overall risk of bias. We used hierarchical summary receiver-operating characteristic (HSROC) curve models for four analyses. -For the first three analyses, IHC was used as the standard for tissue reference assay: i)18F-FES PET performance for nonbreast lesions in patients with metastatic breast cancer; ii)18F-FES PET performance for breast tumors; iii)18F-FES PET performance for all lesions (combined analysis); -The last analysis assesses 18F-FES PET performance with all evaluable studies, which used a variety of standards for the tissue reference. Results PubMed and EMBASE searches identified 103 breast cancer studies involving 18F-FES PET, and 12 studies met the criteria for inclusion in our meta-analysis. Results are presented in Table 1. Tests of homogeneity did not find differences in sensitivity or specificity among the studies in the primary analysis or other analyses with IHC as the tissue reference standard. Examining all tumor sites and all breast cancer stages, our results are consistent with other published meta-analyses (Table 2). Conclusion A strong correlation has been demonstrated between ER status determined by IHC of tissue from a single lesion and 18F-FES PET in this meta-analysis, which validates the accuracy of 18F-FES PET assessment of metastatic ER status. These results suggest that 18F-FES PET is useful for characterization of ER status of metastatic breast cancer lesions. Moreover, 18F-FES has been approved by the FDA in May 2020 as an adjunct to biopsy in recurrent and metastatic breast cancer. Citation Format: Peter Webner, Brenda F. Kurland, Jay R. Wiggins, Amandine Coche, Charlotte Fontan, Yann Bouvet, Chaitanya Divgi, Hannah M. Linden. Fluoroestradiol F18 positron emission tomography diagnostic performance to characterize estrogen receptor status in breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS3-06.