title: Evaluation of18F-fluorothymidine positron emission tomography ([18F]FLT-PET/CT) methodology in assessing early response to chemotherapy in patients with gastro-oesophageal cancer.
abstract: BACKGROUND
  3'-Deoxy-3'-[18F]fluorothymidine ([18F]FLT) PET has limited utility in abdominal imaging due to high physiological hepatic uptake of a tracer. We evaluated [18F]FLT-PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (KSF) to improve tumour visualisation in patients with locally advanced and metastatic gastro-oesophageal cancer and as a marker of early response to chemotherapy. Dynamic [18F]FLT-PET/CT data were collected before and 3 weeks post first cycle of chemotherapy. Changes in tumour [18F]FLT-PET/CT variables were determined. Response was determined on contrast-enhanced CT after three cycles of therapy using RECIST 1.1.
  
  
  RESULTS
  Ten patients were included. Following application of the KSF, visual distinction of all oesophageal and/or gastric tumours was observed in [18F]FLT-PET images. Among the nine patients available for response evaluation (RECIST 1.1), three patients had responded (partial response) and six patients were non-responders (stable disease). There was a significant association between Ki-67 and all baseline [18F]FLT-PET parameters. Area under the curve (AUC) from 0 to 1 min was associated with treatment response.
  
  
  CONCLUSIONS
  The results of this study indicate that application of the KSF allowed accurate visualisation of both primary and metastatic lesions following imaging with the proliferation marker, [18F]FLT-PET/CT. However, [18F]FLT-PET uptake parameters did not correlate with response. Instead, we observe significant changes in tracer delivery following chemotherapy suggesting that further [18F]FLT-PET/CT studies in this tumour type should be undertaken with caution.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK. r.sharma@imperial.ac.uk.|Medical Oncology and Clinical Pharmacology, Imperial College London, Hammersmith Campus, Du Cane Road, W12 0HS, London, UK. r.sharma@imperial.ac.uk.
authors.forename: R
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Mapelli
authors.affiliation: Department of Gastro-Oesophageal Surgery, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: G B
authors.initials: GB
authors.lastname: Hanna
authors.affiliation: Department of Pathology, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Goldin
authors.affiliation: Department of Oncology, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Power
authors.affiliation: Department of Radiology/Nuclear Medicine, Imperial College Healthcare NHS Trust, London, UK.|Medical Oncology and Clinical Pharmacology, Imperial College London, Hammersmith Campus, Du Cane Road, W12 0HS, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Al-Nahhas
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Merchant
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Ramaswami
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Challapalli
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.|Department of Radiology/Nuclear Medicine, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: T
authors.initials: T
authors.lastname: Barwick
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: E O
authors.initials: EO
authors.lastname: Aboagye
keywords: Chemotherapy; Early response; Gastro-oesophageal cancer; RECIST 1.1; [18 F]FLT-PET