title: Positron emission tomography of tumour [(18)F]fluoroestradiol uptake in patients with acquired hormone-resistant metastatic breast cancer prior to oestradiol therapy.
abstract: OBJECTIVE
  Whereas anti-oestrogen therapy is widely applied to treat oestrogen receptor (ER) positive breast cancer, paradoxically, oestrogens can also induce tumour regression. Up-regulation of ER expression is a marker for oestrogen hypersensitivity. We, therefore, performed an exploratory study to evaluate positron emission tomography (PET) with the tracer 16α-[(18)F]fluoro-17β-oestradiol ((18)F-FES) as potential marker to select breast cancer patients for oestradiol therapy.
  
  
  METHODS
  Eligible patients had acquired endocrine-resistant metastatic breast cancer that progressed after ≥2 lines of endocrine therapy. All patients had prior ER-positive histology. Treatment consisted of oestradiol 2 mg, three times daily, orally. Patients underwent (18)F-FES-PET/CT imaging at baseline. Tumour (18)F-FES-uptake was quantified for a maximum of 20 lesions and expressed as maximum standardised uptake value (SUVmax). CT-scan was repeated every 3 months to evaluate treatment response. Clinical benefit was defined as time to radiologic or clinical progression ≥24 weeks.
  
  
  RESULTS
  (18)F-FES uptake, quantified for 255 lesions in 19 patients, varied greatly between lesions (median 2.8; range 0.6-24.3) and between patients (median 2.5; range 1.1-15.5). Seven (37%) patients experienced clinical benefit of oestrogen therapy, eight progressed (PD), and four were non-evaluable due to side effects. The positive and negative predictive value (PPV/NPV) of (18)F-FES-PET for response to treatment were 60% (95% CI: 31-83%) and 80% (95% CI: 38-96%), respectively, using SUVmax >1.5.
  
  
  CONCLUSIONS
  (18)F-FES-PET may aid identification of patients with acquired antihormone resistant breast cancer that are unlikely to benefit from oestradiol therapy.
authors.affiliation: Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands.
authors.forename: Michel
authors.initials: M
authors.lastname: van Kruchten
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Andor W J M
authors.initials: AWJM
authors.lastname: Glaudemans
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Erik F J
authors.initials: EFJ
authors.lastname: de Vries
authors.affiliation: Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands.
authors.forename: Carolien P
authors.initials: CP
authors.lastname: Schröder
authors.affiliation: Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands.
authors.forename: Elisabeth G E
authors.initials: EGE
authors.lastname: de Vries
authors.affiliation: Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands. g.a.p.hospers@umcg.nl.
authors.forename: Geke A P
authors.initials: GAP
authors.lastname: Hospers
mesh_terms: D000328:Adult; D000368:Aged; D001692:Biological Transport; D014408:Biomarkers, Tumor / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D004958:Estradiol / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D004958:Estradiol; C043436:16-fluoroestradiol