Can 18F-Fluoroestradiol positron emission tomography become a new imaging standard in the estrogen receptor-positive breast cancer patient: A prospective comparative study with 18F-Fluorodeoxyglucose positron emission tomography?

Abstract

Correct staging is the most crucial for the treatment outcome in cancer management. Molecular imaging with ¹⁸F-fluoroestradiol (FES) positron emission tomography-computed tomography (PET-CT) targets estrogen receptor (ER) and may have a higher incremental value in diagnosis by aiding specificity. We enrolled 12 female breast cancer patients prospectively and did ¹⁸F-FES PET-CT and ¹⁸F-fluorodeoxyglucose (FDG) PET-CT within 1 week interval time. Lesion detection sensitivity was compared for a total number of lesions and for nonhepatic lesions only by McNemar test. ¹⁸F-FES PET-CT was taken as reference in case of indeterminate lesions. The incremental value reported by identifying ¹⁸F-FES exclusive lesions and by characterization of ¹⁸F-FDG indeterminate lesions. Spearman rank test was used to correlate ER expression and maximum standardized uptake value (SUVmax). Two ER-negative patients with no ¹⁸F-FES uptake were excluded. Ten ER-positive patients with 154 disease lesions were finally analyzed. ¹⁸F-FDG picked-up 142 lesions (sensitivity 92.21%), whereas ¹⁸F-FES picked-up 116 lesions (sensitivity 75.32%) and this difference was statistically significant. For nonhepatic lesions (<i>n</i> = 136) detectability, ¹⁸F-FDG picked-up 124 (sensitivity 91.18%), whereas ¹⁸F-FES picked-up 116 (sensitivity 85.29%) lesions and this difference was not statistically significant. Beside 12 exclusive lesions, ¹⁸F-FES characterized 41 (27.5%) ¹⁸F-FDG indeterminate lesions. Overall ¹⁸F-FES impacted 20% patient management. The positive trend was also seen with ¹⁸F-FES SUVmax with ER expression and negative with ¹⁸F-FDG SUVmax. We conclude, ¹⁸F-FDG has overall better sensitivity than ¹⁸F-FES PET-CT, however for nonhepatic metastasis difference was not significant. ¹⁸F-FES PET-CT better-characterized lesions and impacted 20% patient management. Therefore, ¹⁸F-FES PET-CT should be used with ¹⁸F-FDG PET-CT in strongly ER expressing patients for better specificity.