title: Stable metabolic disease on FDG-PET provides information on response to endocrine therapy for breast cancer.
abstract: BACKGROUND
  The aim of this study was to assess whether outcome in advanced breast cancer patients is related to metabolic response to endocrine therapy determined by fluorodeoxyglucose positron-emission tomography (FDG-PET).
  
  
  METHODS
  We retrospectively identified 21 consecutive breast cancer patients receiving endocrine therapy for metastatic disease (mean number of previous therapies 3.6±3.5). All patients had been evaluated with at least 2 FDG-PETs. The first scan was performed by initiation of endocrine therapy. The second scan was performed after a mean of 3.8±1.14 months. Seventy-two FDG-avid lesions were identified and followed. The mean change in SUVmax (ΔSUVmax) was calculated per patient.
  
  
  RESULTS
  ΔSUVmax dichotomized using the group median as cut-off (8.6%) was predictive of progression-free survival (PFS). The median PFS for the response-group (N.=10, median ΔSUVmax -20.9%) was 10.1 months. The median PFS for the progressive disease-group (N.=11, median ΔSUVmax 40.6%) was 6.7 months (log-rank testing P=0.033).
  
  
  CONCLUSIONS
  Our data suggest that breast cancer patients under hormonal therapy with stable disease on FDG-PET have a longer PFS when compared to non-responders. This finding is new, supporting the value of endocrine therapy among patients with advanced breast cancer.
authors.affiliation: Department of Medical Oncology, Ghent University Hospital, Ghent, Belgium - vibeke.kruse@uzgent.be.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Kruse
authors.affiliation: Department of Radiology and Nuclear Medicine, University of Ghent, Ghent, Belgium.|Department of Nuclear Medicine, Groeninge University Hospital, Kortrijk, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: VAN DE Wiele
authors.affiliation: Department of Nuclear Medicine, Groeninge University Hospital, Kortrijk, Belgium.|Subfaculty of Medicine, Catholic University of Leuven, Kortrijk, Belgium.
authors.forename: Alex
authors.initials: A
authors.lastname: Maes
authors.affiliation: Department of Radiotherapy and Medical Oncology, Groeninge University Hospital, Kortrijk, Belgium.
authors.forename: Marleen
authors.initials: M
authors.lastname: Borms
authors.affiliation: Subfaculty of Medicine, Catholic University of Leuven, Kortrijk, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Pottel
authors.affiliation: Department of Medical Oncology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Simon
authors.initials: S
authors.lastname: VAN Belle
authors.affiliation: Department of Medical Oncology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Veronique
authors.initials: V
authors.lastname: Cocquyt
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006728:Hormones / Q000627:therapeutic use*; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D006728:Hormones; D018396:Mucin-1; D019788:Fluorodeoxyglucose F18