title: ¹⁸F-FDG PET/contrast enhanced CT in the standard surveillance of high risk colorectal cancer patients.
abstract: OBJECTIVE
  To assess the accuracy of FDG-PET/contrast enhanced CT (FDG-PET/ceCT) in the detection of unsuspected recurrence of colorectal cancer (CRC) in patients with high risk of relapse.
  
  
  METHODS
  Thirty-three patients (14 females and 19 males, mean age: 62, range: 41-78), with CRC in complete remission, were prospectively included. All patients underwent FDG-PET/ceCT (58 studies). FDG-PET/ceCT was requested in the surveillance setting, and performed following a standardized protocol. A portal venous phase CT scan was performed after the injection of iodinated contrast agent. An individual and combined assessment of both techniques (PET and ceCT) was performed. Concordant and discordant findings of PET, ceCT and FDG-PET/ceCT were compared in a patient-based and a lesion-based analysis. The final diagnosis, recurrence or disease free status (DFS), were established by histopathology or clinical/radiological follow-up of at least 6 months.
  
  
  RESULTS
  Seven out of 33 patients had a confirmed recurrence and the rest of patients had a DFS. In a patient-based analysis the sensitivity and specificity of PET, ceCT and PET/ceCT was of 86% and 88%, 86% and 92%, 86% and 85%, respectively. Attending to the lesion-based analysis, the sensitivity for PET, ceCT and PET/ceCT was of 56%, 71% and 97%, respectively. Both techniques showed a good concordance in the establishment of the final patient status. However, on a lesion-based analysis, no concordance was observed between them.
  
  
  CONCLUSIONS
  PET and ceCT seem to have similar value in the detection of unsuspected recurrence of CRC in a patient-based analysis. However, the combined assessment of PET/ceCT improves the accuracy in the lesion-based analysis.
authors.affiliation: Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain. Electronic address: gjimenez91@yahoo.com.
authors.forename: Germán Andrés
authors.initials: GA
authors.lastname: Jiménez Londoño
authors.affiliation: Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Ana María
authors.initials: AM
authors.lastname: García Vicente
authors.affiliation: Department of Oncology, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Sánchez Pérez
authors.affiliation: Department of Radiology, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Fátima
authors.initials: F
authors.lastname: Jiménez Aragón
authors.affiliation: Investigation Unit, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: León Martin
authors.affiliation: Department of Oncology, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Juana María
authors.initials: JM
authors.lastname: Cano Cano
authors.affiliation: Department of Radiology, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Domínguez Ferreras
authors.affiliation: Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Ober Van
authors.initials: OV
authors.lastname: Gómez López
authors.affiliation: Department of Oncology, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Espinosa Arranz
authors.affiliation: Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain.
authors.forename: Ángel María
authors.initials: ÁM
authors.lastname: Soriano Castrejón
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Colorectal cancer; Contrast enhanced CT scan; FDG PET; Recurrence; Surveillance