PET/CT with <sup>18</sup>F-Fluoroestradiol in First Diagnosed Breast Cancer. A Pilot Study

Abstract

   Purpose: To evaluate the informativity of PET/CT with 18F-FES in determining estrogen receptor (ER) positivity in breast tumor tissue, as well as in regional lymph nodes or distant metastatic foci.   Material and methods: The data of 30 patients who underwent PET/CT with 18F-FES performed at the stage of primary diagnosis were retrospectively analyzed. The study included patients before the start of specific treatment or on the background of neoadjuvant hormone therapy, with previously determined expression of ER according to the results of IGC. 14 patients underwent 18F-FDG PET/CT with 2–7 days difference between both PET/CT.   Results: In our study, the mean SUVmax value in the primary tumor focus was 4.8, the lowest SUVmax = 1.61, and the highest SUVmax = 18.86. 18F-FES accumulation considered suspicious for metastatic lesion in axillary lymph nodes on the affected side was detected in 16 patients (56 %), mean SUVmax = 5.2, lowest SUVmax = 0.99, highest SUVmax = 11.54. On subsequent histological examination, tumor changes in axillary lymph nodes were confirmed in 16/16 patients.   Conclusion: PET/CT with 18F-FES is a diagnostic method for noninvasive evaluation of ER expression in tumor foci, which can complement the data of traditional diagnostic methods and has a significant clinical potential. In our study, the results of PET/CT with 18F-FES coincided with the data of immunohistochemical study in 100 % of cases.