18F-Fluoroestradiol Positron Emission Tomography in Breast Cancer Patients: Systematic Review of the Literature & Meta-Analysis.

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.