Assessment of Estrogen Receptor Expression in Epithelial Ovarian Cancer Patients Using 16α-¹⁸F-Fluoro-17β-Estradiol PET/CT

Abstract

The estrogen receptor α (ERα) is expressed in approximately 70% of ovarian cancer tumors. PET of tumor ERα expression with the tracer 16α-18 F-fluoro-17β-estradiol ( 18 F-FES) may be valuable to select ovarian cancer patients for endocrine therapy. The aim of this study was to evaluate the feasibility of 18 F-FES PET to determine tumor ERα expression noninvasively in epithelial ovarian cancer patients. Methods: 18 F-FES PET/CT was performed shortly before cytoreductive surgery. Tumor 18 F-FES uptake was quantified for all lesions 10 mm or greater on CT and expressed as maximum standardized uptake value. 18 F-FES PET/CT findings were compared with histology and immunohistochemistry for ERα, ERβ, and progesterone receptor. Receptor expression was scored semiquantitatively using H-scores (percentage of positive tumor cells · staining intensity). The optimum threshold to discriminate ER-positive and -negative lesions was determined by receiver-operating-characteristic analysis. Results: In the 15 included patients with suspected ovarian cancer, 32 measurable lesions greater than 10 mm were present on CT. Tumor 18 F-FES uptake could be quantified for 28 lesions (88%), and 4 lesions were visible but nonquantifiable because of high uptake in adjacent tissue. During surgery, histology was obtained of 23 of 28 quantified lesions (82%). Quantitative 18 F-FES uptake correlated with the semiquantitative immunoscore for ERα (ρ 5 0.65, P , 0.01) and weakly with progesterone receptor expression (ρ 5 0.46, P 5 0.03) and was not associated with ERβ expression (ρ 5 0.21, P 5 0.33). The optimum threshold to discriminate ERα-positive and ERα-negative lesions was a maximum standardized uptake value greater than 1.8, which provided a 79% sensitivity, 100% specificity, and area under the curve of 0.86 (95% confidence interval, 0.70-1.00). In 2 of 7 patients with cytology/histology available at primary diagnosis and at debulking surgery, immunohistochemical ERα expression had changed over time. 18 F-FES PET was in accordance with histology at debulking surgery but not at primary diagnosis, indicating that 18 F-FES PET could provide reliable information about current tumor ERα status. Conclusion: 18 F-FES PET/CT can reliably assess ERα status in epithelial ovarian cancer tumors and metastases noninvasively. Evaluation of the predictive value of 18 F-FES PET/CT for endocrine therapy in epithelial ovarian cancer patients is warranted.

A preliminary study of 18F-FES PET/CT in predicting metastatic breast cancer in patients receiving docetaxel or fulvestrant with docetaxel

“…Previous studies have successfully validated that 18 F-FES PET uptake correlates well with immunohistochemical (IHC) scoring for ER 23–28 . Thus, we hypothesized that we could use 18 F-FES PET to monitor the change in ER during combination treatment, with the potential to predict prognosis.…”

18F-Fluoroestradiol PET: Current Status and Potential Future Clinical Applications

“…Up to 70% of epithelial ovarian cancers express ER at baseline (51), and 18 F-FES PET has the ability to localize primary and metastatic lesions in such cancers (52,53). Van Kruchten et al studied the utility of 18 F-FES PET in 15 patients with suspected ovarian cancer, demonstrating a correlation between lesion 18 F-FES uptake and immunohistochemical ER expression, as well as 79% sensitivity and 100% specificity using an SUV threshold of 1.8 (53).…”

“…Van Kruchten et al studied the utility of 18 F-FES PET in 15 patients with suspected ovarian cancer, demonstrating a correlation between lesion 18 F-FES uptake and immunohistochemical ER expression, as well as 79% sensitivity and 100% specificity using an SUV threshold of 1.8 (53).…”

Diagnostic imaging using positron emission tomography for gynecological malignancy

“…Uptake of 18 F-FES can reflect ER status and was associated with immunohistological ER-α expression, suggesting that 18 F-FES PET could have predictive value in assessing response to hormone treatment for ovarian cancer. 110,111 Moreover, as another tracer to predict treatment response, …”