title: Clinical validation of FDG-PET/CT in the radiation treatment planning for patients with oesophageal cancer.
abstract: BACKGROUND
  The aim of this prospective study was to determine the proportion of locoregional recurrences (LRRs) that could have been prevented if radiotherapy treatment planning for oesophageal cancer was based on PET/CT instead of CT.
  
  
  METHODS
  Ninety oesophageal cancer patients, eligible for high dose (neo-adjuvant) (chemo)radiotherapy, were included. All patients underwent a planning FDG-PET/CT-scan. Radiotherapy target volumes (TVs) were delineated on CT and patients were treated according to the CT-based treatment plans. The PET images remained blinded. After treatment, TVs were adjusted based on PET/CT, when appropriate. Follow up included CT-thorax/abdomen every 6months. If LRR was suspected, a PET/CT was conducted and the site of recurrence was compared to the original TVs. If the LRR was located outside the CT-based clinical TV (CTV) and inside the PET/CT-based CTV, we considered this LRR possibly preventable.
  
  
  RESULTS
  Based on PET/CT, the gross tumour volume (GTV) was larger in 23% and smaller in 27% of the cases. In 32 patients (36%), >5% of the PET/CT-based GTV would be missed if the treatment planning was based on CT. The median follow up was 29months. LRRs were seen in 10 patients (11%). There were 3 in-field recurrences, 4 regional recurrences outside both CT-based and PET/CT-based CTV and 3 recurrences at the anastomosis without changes in TV by PET/CT; none of these recurrences were considered preventable by PET/CT.
  
  
  CONCLUSIONS
  No LRR was found after CT-based radiotherapy that could have been prevented by PET/CT. The value of PET/CT for radiotherapy seems limited.
authors.affiliation: Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: c.t.muijs@umcg.nl.
authors.forename: Christina T
authors.initials: CT
authors.lastname: Muijs
authors.affiliation: Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Jannet C
authors.initials: JC
authors.lastname: Beukema
authors.affiliation: Department of Radiation Oncology, Medical Spectrum Twente, Enschede, The Netherlands.
authors.forename: Dankert
authors.initials: D
authors.lastname: Woutersen
authors.affiliation: Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Veronique E
authors.initials: VE
authors.lastname: Mul
authors.affiliation: Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Maaike J
authors.initials: MJ
authors.lastname: Berveling
authors.affiliation: Department of Molecular Imaging and Nuclear Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Nuclear Medicine, Stellenbosch University, South Africa.
authors.forename: Jan
authors.initials: J
authors.lastname: Pruim
authors.affiliation: Department of Radiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: van der Jagt
authors.affiliation: Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Geke A P
authors.initials: GA
authors.lastname: Hospers
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Henk
authors.initials: H
authors.lastname: Groen
authors.affiliation: Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: John Th
authors.initials: JT
authors.lastname: Plukker
authors.affiliation: Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Langendijk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000517:prevention & control*; D049268:Positron-Emission Tomography / Q000379:methods; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG-PET/CT; Oesophageal cancer; Radiotherapy planning