title: 18F-FDG PET/CT for Early Postradiotherapy Assessment in Solitary Bone Plasmacytomas.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the performance and possible prognostic value of early (18)F-FDG PET/CT (FDG PET/CT) assessment after radiotherapy (RT) in patients with solitary bone plasmacytoma (SBP).
  
  
  METHODS
  Twenty-one patients affected by SBP who underwent FDG PET/CT scan for early restaging (≤6 months) postradiotherapy assessment were selected from the PET databases of University College London Hospital of London and San Raffaele Hospital of Milan. Patients with no abnormal uptake were classified as having no pathologic uptake (NPU). A SUV(max) cutoff value of 4 was chosen to discriminate minimal residual uptake (MRU; SUV(max) ≤ 4) from pathologic uptake (PU, SUV(max) >4). Progression-free survival (PFS) rate was estimated using Kaplan-Meier curves and Cox regression analysis.
  
  
  RESULTS
  In 10 of 21 patients restaged by FDG PET/CT, further previous baseline scan was available also at staging, and results showed positive findings at the level of all biopsy-proven disease areas.Considering MRU as PU, FDG PET/CT showed a sensitivity and specificity of 86% and 29%, respectively. Using SUV(max) >4 as the cutoff, sensitivity and specificity were 86% and 93%, respectively. Kaplan-Meier curves revealed a significant difference in PFS probability between patients classified as positive on FDG PET/CT using a cutoff of SUV(max) >4 (PU) and those classified as negative (NPU + MRU) (log-rank, Mantel-Cox, P = 0.009; χ(2) = 6.85). Cox regression analysis of PFS using SUV(max) >4 as cutoff revealed an interesting relation in prediction of progression (HR, 9.458).
  
  
  CONCLUSIONS
  (18)F-FDG PET/CT for early restaging after RT in patients with SBP should be considered carefully in view of the lack of specificity of a low SUV(max) value. The good correlation between a high SUV(max) value and follow-up suggests a possible prognostic role for FDG PET/CT in disease progression at early restaging after RT.
authors.affiliation: From the *University of Milano-Bicocca, Milan, Italy; †Nuclear Medicine Department, IRCSS San Raffaele Scientific Institute, Milan, Italy; ‡University Hospital Sant'Orsola-Malpighi, Bologna, Italy; §Nuclear Medicine and PET-CT Department, Metropolitan Hospital, New Faliro, Greece; and ∥Department of Nuclear Medicine, University College London Hospital, London, United Kingdom.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Alongi
authors.forename: Lucia
authors.initials: L
authors.lastname: Zanoni
authors.forename: Elena
authors.initials: E
authors.lastname: Incerti
authors.forename: Federico
authors.initials: F
authors.lastname: Fallanca
authors.forename: Paola
authors.initials: P
authors.lastname: Mapelli
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Papathanasiou
authors.forename: Luigi
authors.initials: L
authors.lastname: Gianolli
authors.forename: Maria
authors.initials: M
authors.lastname: Picchio
authors.forename: Jamshed
authors.initials: J
authors.lastname: Bomanji
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D010954:Plasmacytoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18