title: Sequential FDG-PET/CT as a biomarker of response to Sunitinib in metastatic clear cell renal cancer.
abstract: OBJECTIVE
  To test the hypothesis that sequential (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is a correlative marker in metastatic clear cell renal cancer (mRCC), patients were treated with sunitinib. Three sequential scans were conducted to determine whether the timing of the investigation was relevant.
  
  
  METHODS
  Forty-four untreated mRCC patients were enrolled into this prospective phase II study. (18)F-FDG-PET/CT scans were conducted before (n = 44) and after 4 weeks (n = 43) and 16 weeks (n = 40) of sunitinib given at standard doses. The primary endpoint was to correlate FDG-PET/CT response (20% reduction in SUV(max)) at 4 and 16 weeks with overall survival (OS).
  
  
  RESULTS
  Forty-three (98%) patients had FDG-PET/CT avid lesions at diagnosis (median SUV(max) = 6.8, range: <2.5-18.4). In multivariate analysis, a high SUV(max) and an increased number of PET-positive lesions correlated with shorter OS [HR: 3.30 (95% CI: 1.36-8.45) and 3.67 (95% CI: 1.43-9.39), respectively]. After 4 weeks of sunitinib, a metabolic response occurred in 24 (57%) patients, but this did not correlate with progression-free survival (HR for responders = 0.87; 95% CI: 0.40-1.99) or OS (HR for responders = 0.80; 95% CI: 0.34-1.85). After 16 weeks of treatment, disease progression on FDG-PET/CT occurred in 28% (n = 12) patients which correlated with a decreased OS and PFS [HR = 5.96 (95% CI: 2.43-19.02) and HR = 12.13 (95% CI: 3.72-46.45), respectively].
  
  
  CONCLUSIONS
  Baseline FDG-PET/CT yields prognostic significant data. FDG-PET/CT responses occur in the majority of patients after 4 weeks of therapy; however, it is not until 16 weeks when the results become prognostically significant.
authors: Department of Nuclear Medicine, University College Hospital, London, UK.
authors: Irfan
authors: I
authors: Kayani
authors: Norbert
authors: N
authors: Avril
authors: Jamshed
authors: J
authors: Bomanji
authors: Simon
authors: S
authors: Chowdhury
authors: Andrea
authors: A
authors: Rockall
authors: Anju
authors: A
authors: Sahdev
authors: Paul
authors: P
authors: Nathan
authors: Peter
authors: P
authors: Wilson
authors: Jonathan
authors: J
authors: Shamash
authors: Kevin
authors: K
authors: Sharpe
authors: Louise
authors: L
authors: Lim
authors: John
authors: J
authors: Dickson
authors: Peter
authors: P
authors: Ell
authors: Andrew
authors: A
authors: Reynolds
authors: Thomas
authors: T
authors: Powles
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography; D011379:Prognosis; D011758:Pyrroles / Q000627:therapeutic use*; D000077210:Sunitinib; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D007211:Indoles; D011758:Pyrroles; D019788:Fluorodeoxyglucose F18; D000077210:Sunitinib