Purpose: The aim of the study was to determine the correlation between 16α-18F-fluoro-
17β-estradiol (18F-FES) uptake and the expression and functionality of estrogen receptors (ERs), as
well as to evaluate the ability of 18F-FES PET to predict the response to hormonal therapy (HT) in
patients with locally advanced or metastatic breast cancer (BC).
Methods: Literature searches in the major literature databases were carried out in order to select
English-language articles dealing with 18F-FES PET and BC. Studies that included patients with BC
undergoing 18F-FES PET alone or in combination with other imaging modalities and included the absolute
numbers of true-positive, true-negative, false-positive and false-negative test results were selected.
Results: We found 23 journal articles, published between 1988 and December 2014, that critically
evaluated the role of 18F-FES PET in BC patients. Two separate meta-analyses were carried out: 1-
to assess the correlation between 18F-FES uptake and ER expression and 2- to determine the predictive
value of 18F-FES in response to HT. For the first, we considered nine selected studies with a total
of 238 patients. A pooled sensitivity of 82% (95% CI: 74-88%) and a pooled specificity of 95%
(95% CI: 86-99%) for the evaluation of ER functional status by 18F-FES PET were found. Seven
studies, with a total of 226 patients, were considered eligible for the analysis of prediction for response.
The pooled sensitivities and specificities were 63.9% (95% CI: 46.2-79.2%) vs. 66.7% (95%
CI: 52.1-79.2%), and 28.6% (95% CI: 17.3-42.2%) vs. 62.1% (95% CI: 48.4-74.5%), for a SUV cutoff
of 1.5 and 2.0, respectively.
Conclusion: A good correlation between 18F-FES uptake and ER expression by immunohistochemistry
emerges, while the role of 18F-FES in predicting the response to endocrine therapy in advanced
BC remains undetermined.