FEStive.

In this prospective study, 181 patients with newly diagnosed metastatic breast cancer underwent imaging with fluoro-estradiol (FES)-PET. They then had biopsies to determine if FES-PET could predict estrogen receptor (ER) status of individual metastases. The sensitivity and specificity for ER expression were 95% and 80%, respectively, and the positive and negative predictive values were 93% and 85%. Quantitatively, FES-PET was even more accurate with a positive predictive value of 99% when the SUVmax was ≥2.5. | van Geel, J Clin Oncol 2022