Abstract
The PET compound 18F-fluoroestradiol (18F-FES) has been developed and tested as an agent for the imaging of estrogen receptor (ER) expression in vivo. 18F-FES uptake has been shown to correlate with ER expression assayed in vitro by radioligand binding; however, immunohistochemistry (IHC) rather than radioligand binding is used most often to measure ER expression in clinical practice. We therefore compared 18F-FES uptake with ER expression assayed in vitro by IHC with both qualitative and semiquantitative measures. Methods: Seventeen patients with primary or metastatic breast cancer were studied with dynamic 18F-FES PET; cancer tissue samples, collected close to the time of imaging, were assayed for ER expression by IHC. For each tumor, partial-volume-corrected measures of 18F-FES uptake were compared with ER expression measured by 3 different ER scoring methods: qualitative scoring (0-31), the Allred score (0-10), and a computerized IHC index. Results: There was excellent agreement (r=0.99) between observers using IHC as well as the different methods of measuring ER content (P < 0.001). ER-negative tumors had 18F-FES partial-volume-corrected standardized uptake values of less than 1.0, whereas ER-positive tumors had values above 1.1. Correlation coefficients for the different measures of ER content and the different measures of 18F-FES uptake ranged from 0.57 to 0.73, with the best correlation being between the computerized IHC index and 18F-FES partial-volume-corrected standardized uptake values. Conclusion: Our results showed good agreement between 18F-FES PET and ER expression measured by IHC. 18F-FES imaging may be a useful tool for aiding in the assessment of ER status, especially in patients with multiple tumors or for tumors that are difficult to biopsy.
Original language | English (US) |
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Pages (from-to) | 367-374 |
Number of pages | 8 |
Journal | Journal of Nuclear Medicine |
Volume | 49 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1 2008 |
Externally published | Yes |
Keywords
- Breast cancer
- Estrogen receptor
- F-FES PET
- IHC
- Tracer uptake
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging