The FES bet.

An critical point for recurrent, metastatic breast cancer is knowing the receptor status, which can frequently change or be heterogeneous. The problem is, that requires obtaining more tissue—often through invasive means. What if there were a PET scan for that? Boom, there is. In this prospective study, 85 patients underwent FES-PET (F-18 linked to estradiol) as part of a workup that included a planned resection or needle biopsy to confirm receptor status. Importantly, participants had to discontinue estrogen blockade prior to imaging. FES-PET was positive in 41% of patients and all of those patients had ER(+) breast cancer. Among the FES-PET negative patients, 20% had ER(+) breast cancer. Put differently, ER(+) status agreement between PET and IHC was 77%, and ER(-) status agreement was 100%. TBL: FES-PET may be an effective way to noninvasively assess receptor status in patients with recurrent or metastatic breast cancer. | Chae, Lancet Oncol 2019