A phase 2 study of 16α-[18F]-fluoro-17β-estradiol positron emission tomography (FES-PET) as a marker of hormone sensitivity in metastatic breast cancer (MBC)

Mol Imaging Biol. 2014 Jun;16(3):431-40. doi: 10.1007/s11307-013-0699-7. Epub 2013 Oct 30.


Purpose: 16α-[(18)F]-fluoro-17β-estradiol positron emission tomography (FES-PET) quantifies estrogen receptor (ER) expression in tumors and may provide diagnostic benefit.

Procedures: Women with newly diagnosed metastatic breast cancer (MBC) from an ER-positive primary tumor were imaged before starting endocrine therapy. FES uptake was evaluated qualitatively and quantitatively, and associated with response and with ER expression.

Results: Nineteen patients underwent FES imaging. Fifteen had a biopsy of a metastasis and 15 were evaluable for response. Five patients had quantitatively low FES uptake, six had at least one site of qualitatively FES-negative disease. All patients with an ER-negative biopsy had both low uptake and at least one site of FES-negative disease. Of response-evaluable patients, 2/2 with low FES standard uptake value tumors had progressive disease within 6 months, as did 2/3 with qualitatively FES-negative tumors.

Conclusions: Low/absent FES uptake correlates with lack of ER expression. FES-positron emission tomography can help identify patients with endocrine resistant disease and safely measures ER in MBC.

Publication types

  • Clinical Trial, Phase II
  • Research Support, N.I.H., Extramural

MeSH terms

  • Breast Neoplasms / diagnostic imaging*
  • Breast Neoplasms / pathology
  • Estradiol*
  • Female
  • Fluorine Radioisotopes*
  • Humans
  • Neoplasm Metastasis / pathology*
  • Positron-Emission Tomography / methods*


  • Fluorine Radioisotopes
  • Estradiol