title: Fluorine-18 fluorodeoxyglucose PET in the preoperative staging of colorectal cancer.
abstract: BACKGROUND
  In patients with colorectal cancer (CC), preoperative evaluation and staging should focus on techniques that might alter the preoperative or intraoperative surgical plan. Conventional imaging methods (CT, MRI) have low accuracy for identifying the depth of tumour infiltration and have limited ability to detect regional lymph node involvement. The aim of this study was to evaluate the utility of FDG-PET in the initial staging of patients with CC in comparison with conventional staging methods and to determine its impact on therapeutic management.
  
  
  METHODS
  One hundred and four patients with a diagnosis of CC (53 males and 51 females; mean age 66.76+/-12.36 years), selected prospectively, were studied for staging using a standard procedure (CT) and FDG-PET. When possible, the reference method was histology.
  
  
  RESULTS
  In 14 patients, surgery was contraindicated by FDG-PET owing to the extent of disease (only 6/14 suspected by CT). FDG-PET revealed four synchronous tumours. For N staging, both procedures showed a relatively high specificity but a low diagnostic accuracy (PET 56%, CT 60%) and sensitivity (PET 21%, CT 25%). For M assessment, diagnostic accuracy was 92% for FDG-PET and 87% for CT. FDG-PET results led to modification of the therapy approach in 50% of patients with unresectable disease. FDG-PET findings were important, revealing unknown disease in 19.2%, changing the staging in 13.46% and modifying the scope of surgery in 11.54% (with a change in the therapeutic approach in 17.85% of those patients with rectal cancer).
  
  
  CONCLUSIONS
  Compared with conventional techniques, FDG-PET appears to be useful in pre-surgical staging of CC, revealing unsuspected disease and impacting on the treatment approach.
authors.affiliation: Department of Nuclear Medicine, Virgen De Las Nieves University Hospital, Granada, Spain.
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Llamas-Elvira
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez-Fernández
authors.forename: Javier
authors.initials: J
authors.lastname: Gutiérrez-Sáinz
authors.forename: Manuel
authors.initials: M
authors.lastname: Gomez-Rio
authors.forename: María
authors.initials: M
authors.lastname: Bellon-Guardia
authors.forename: Carlos
authors.initials: C
authors.lastname: Ramos-Font
authors.forename: Angel Custodio
authors.initials: AC
authors.lastname: Rebollo-Aguirre
authors.forename: Dolores
authors.initials: D
authors.lastname: Cabello-García
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferrón-Orihuela
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D019275:Radiopharmaceuticals / Q000627:therapeutic use*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18