Purpose. We compared the clinical value of 16a-18F-fluoro-17b-estradiol ( 18 F-FES) positron emission tomography (PET)/ computed tomography (CT) and 18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) PET/CT and investigated whether and how 18 F-FES PET/CT affects the implemented management of newly diagnosed estrogen receptor positive breast cancer patients. Materials and Methods. We retrospectively analyzed 19 female patients newly diagnosed with immunohistochemistry-confirmed estrogen receptor (ER)-positive breast cancer who underwent 18 F-FES and 18 F-FDG PET/CT within 1 week in our center. The sensitivity of 18 F-FES and 18 F-FDG in diagnosed lesions were compared. To investigate the definite clinical impact of 18 F-FES on managing patients with newly diagnosed ER positive breast cancer, we designed two kinds of questionnaires. Referring physicians completed the first questionnaire based on the 18 F-FDG report to propose the treatment regime, and the second was completed immediately after reviewing the imaging report of 18 F-FES to indicate intended management changes. Results. In total, 238 lesions were analyzed in 19 patients with newly diagnosed ER-positive breast cancer. Lesion detection was achieved in 216 sites with 18 F-FES PET and in 197 sites with 18 F-FDG PET/CT. These results corresponded to sensitivities of 90.8% for 18 F-FES versus 82.8% for 18 F-FDG PET/CT in diagnosed lesions. Thirty-five physicians were given the questionnaires referring to the treatment strategy, with 27 of them completing both questionnaires. The application of 18 F-FES in addition to 18 F-FDG PET/CT changed the management in 26.3% of the 19 patients with newly diagnosed ER-positive breast cancer. Conclusion. Performing 18 F-FES PET/CT in newly diagnosed ER-positive breast cancer patients increases the value of diagnosis equivocal lesions and treatment management compared with 18 F-FDG PET/CT. The Oncologist 2019;24:e1277-e1285 Implications for Practice: This study investigated whether 16a-18F-fluoro-17b-estradiol ( 18 F-FES) positron emission tomography (PET)/computed tomography (CT) affects the clinical management of patients with newly diagnosed estrogen receptor (ER)-positive breast cancer. Physicians completing two questionnaires comparing the clinical impact of 18F-FES and 18F-FDG on individual management plans in patients with newly diagnosed ER-positive breast cancer confirmed that 18F-FES scans led to change in management in 26.3% of the 19 patients with newly diagnosed ER positive breast cancer. This retrospective study indicates the potential impact of 18F-FES PET/CT on intended management of patients with newly diagnosed estrogen receptor positive breast cancer in comparison to 18F-fluoro-2-deoxy-D-glucose PET/CT.

No abstract