RT Journal Article SR Electronic T1 Androgen and Estrogen Receptor Imaging in Metastatic Breast Cancer Patients as a Surrogate for Tissue Biopsies JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1906 OP 1912 DO 10.2967/jnumed.117.193649 VO 58 IS 12 A1 Clasina M. Venema A1 Lemonitsa H. Mammatas A1 Carolina P. Schröder A1 Michel van Kruchten A1 Giulia Apollonio A1 Andor W.J.M. Glaudemans A1 Alfons H.H. Bongaerts A1 Otto S. Hoekstra A1 Henk M.W. Verheul A1 Epi Boven A1 Bert van der Vegt A1 Erik F.J. de Vries A1 Elisabeth G.E. de Vries A1 Ronald Boellaard A1 Catharina W. Menke van der Houven van Oordt A1 Geke A.P. Hospers YR 2017 UL http://jnm.snmjournals.org/content/58/12/1906.abstract AB In addition to the well-known estrogen receptor (ER) and human epidermal growth factor receptor 2, the androgen receptor (AR) is also a potential drug target in breast cancer treatment. Whole-body imaging can provide information across lesions within a patient. ER expression in tumor lesions can be visualized by 18F-fluoroestradiol (18F-FES) PET, and AR expression has been visualized in prostate cancer patients with 18F-fluorodihydrotestosterone (18F-FDHT) PET. Our aim was to assess the concordance between 18F-FDHT and 18F-FES PET and tumor AR and ER expression measured immunohistochemically in patients with metastatic breast cancer. Methods: Patients with ER-positive metastatic breast cancer were eligible for the study, irrespective of tumor AR status. The concordance of 18F-FDHT and 18F-FES uptake on PET with immunohistochemical expression of AR and ER in biopsies of corresponding metastases was analyzed. Patients underwent 18F-FDHT PET and 18F-FES PET. A metastasis was biopsied within 8 wk of the PET procedures. Tumor samples with more than 10% and 1% nuclear tumor cell staining were considered, respectively, AR- and ER-positive. Correlations between PET uptake and semiquantitative immunohistochemical scoring (percentage positive cells × intensity) were calculated. The optimum threshold of SUV to discriminate positive and negative lesions for both AR and ER was determined by receiver-operating-characteristic analysis. Results: In the 13 evaluable patients, correlation (R2) between semiquantitative AR expression and 18F-FDHT uptake was 0.47 (P = 0.01) and between semiquantitative ER expression and 18F-FES uptake 0.78 (P = 0.01). The optimal cutoff for AR-positive lesions was an SUVmax of 1.94 for 18F-FDHT PET, yielding a sensitivity of 91% and a specificity of 100%; the optimal cutoff was an SUVmax of 1.54 for 18F-FES PET, resulting in a sensitivity and specificity of 100% for ER. Conclusion: 18F-FDHT and 18F-FES uptake correlate well with AR and ER expression levels in representative biopsies. These results show the potential use of whole-body imaging for receptor status assessment, particularly in view of biopsy-associated sampling errors and heterogeneous receptor expression in breast cancer metastases.