title: FDG avidity at PET/CT during adjuvant hormonal therapy in patients with breast cancer.
abstract: BACKGROUND
  We aim to retrospectively evaluate the impact of hormone therapy (HT) on FDG avidity of metastatic lesions in patients with breast cancer (BC) undergoing PET/CT.
  
  
  METHODS
  Three hundred eight patients with BC were scanned with PET/CT at 2 Italian institutions (mean time from diagnosis 4 yrs, range: 1-24 yrs). Main indications for PET/CT were elevation of tumor markers (34.4%) and clinical or radiological suspicion of relapse (65.6%). The diagnostic accuracy of FDG PET/CT was computed according to the standard method. Student t test was used to assess the mean differences between the study groups, whereas categorical data were compared with chi-square test. Significance was set at P <0.05.
  
  
  RESULTS
  Two hundred sixty-four patients with positive estrogen receptor and who had received adjuvant HT were included in the analysis. At the time of PET/CT scan, HT was ongoing in 176 patients (66.7%) and 88 (33.3%) had completed adjuvant HT. Ninety-eight (55.7%) patients on HT and 59 (67%) off HT had a positive PET/CT; therefore, the scan resulted negative in the remaining 107 patients, 78 and 29 on and off HT, 44.3% and 33%, respectively (P < 0.001). At a median follow-up of 7 months (range 1-48 mos), disease recurrence was confirmed in either clinical or radiological examinations in 126 (47.7%) patients; 72 (40.9%) versus 54 (61.4%) patients on and off HT, respectively (P < 0.005). True-positive PET/CT results were found in 82% and 91% of patients on and off HT, respectively, whereas it failed to identify disease relapse in 13 (18%) and 5 (9%) patients on and off HT, respectively.
  
  
  CONCLUSIONS
  In our series, FDG PET/CT shows a similar diagnostic accuracy in detecting disease relapse between patients with BC on adjuvant HT versus those who have completed therapy. These preliminary results suggest that the glucose metabolism is not altered by hormonal suppression at the time of the scan.
authors.affiliation: From the *Radiotherapy and Nuclear Medicine Unit, Istituto Oncologico Veneto IOV-IRCCS, Padova; †Service of Oncology, Institute for Cancer Research and Treatment, Candiolo; ‡Service of Nuclear Medicine, Institute for Cancer Research and Treatment, Candiolo; and §Oncology Unit 2, Istituto Oncologico Veneto IOV-IRCCS, Padova, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Evangelista
authors.forename: Stefania
authors.initials: S
authors.lastname: Redana
authors.forename: Manuela
authors.initials: M
authors.lastname: Racca
authors.forename: Elena
authors.initials: E
authors.lastname: Geuna
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Vinante
authors.forename: Giulia
authors.initials: G
authors.lastname: Zago
authors.forename: Valentina
authors.initials: V
authors.lastname: De Carolis
authors.forename: Cristina
authors.initials: C
authors.lastname: Ghiotto
authors.forename: Giorgio
authors.initials: G
authors.lastname: Saladini
authors.forename: Teresio
authors.initials: T
authors.lastname: Varetto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006728:Hormones / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D006728:Hormones; D019788:Fluorodeoxyglucose F18