FDG and FES PET images at four time points: T1: prior to initiation of endocrine
therapy; T2: after response to endocrine therapy; T3: at subsequent disease
progression on endocrine therapy; and T4: at disease progression on
chemotherapy. This suggested an increase in the tumor’s capability to
bind estradiol at the time of disease progression on chemotherapy, suggesting
increased ER expression.
From Currin E, Peterson LM, Schubert EK, et al. Temporal Heterogeneity of
Estrogen Receptor Expression in Bone-Dominant Breast Cancer: 18F-Fluoroestradiol
PET Imaging Shows Return of ER Expression. J Natl Compr Canc
Netw. 2016;14:144–147; with permission.