title: Diagnostic accuracy of colorectal cancer staging with whole-body PET/CT colonography.
abstract: BACKGROUND
  Staging of patients with colorectal cancer often requires a multimodality, multistep imaging approach. Colonography composed of a combined modality of positron emission tomography (PET) and computed tomography (CT) provides whole-body tumor staging in a single session.
  
  
  OBJECTIVE
  To determine the staging accuracy of whole-body PET/CT colonography compared with the staging accuracies of CT followed by PET (CT + PET) and CT alone and to evaluate the effect of PET/CT colonography on therapy planning compared with conventional staging (CT of the abdomen and thorax and optical colonoscopy).
  
  
  METHODS
  Prospective study of 47 patients enrolled between May 2004 and June 2006 with clinical findings and optical colonoscopy that suggested primary colorectal cancer (mean [SD] age, 71 [11] years; range, 47-92 years). Patients underwent whole-body PET/CT colonography 1 day after colonoscopy. The study was conducted at a university hospital with a mean (SD) follow-up of 447 (140) days (range, 232-653 days).
  
  
  METHODS
  Correct classification of overall TNM stage using PET/CT colonography compared with CT + PET and CT alone. Secondary outcome measures were the accurate assessment of T-stage, N-stage, and M-stage by PET/CT colonography compared with CT + PET and CT alone and the effect of PET/CT colonography on therapy planning.
  
  
  RESULTS
  Of the 47 patients with a total of 50 lesions, the overall TNM stage was correctly determined for 37 lesions with PET/CT colonography (74%; 95% confidence interval [CI], 60%-85%), 32 lesions with CT + PET (64%; 95% CI, 49%-77%), and 26 lesions with CT alone with a 0.7-cm node threshold (52%; 95% CI, 37%-66%). Compared with optimized abdominal CT staging alone, PET/CT colonography was significantly more accurate in defining TNM stage (difference, 22%; 95% CI, 9%-36%; P=.003), which was mainly based on a more accurate definition of the T-stage. Differences were not detected for defining N-stage between PET/CT colonography and CT alone with a threshold of 0.7 cm for malignant nodes but were detected with a threshold of 1 cm. Differences were not detected in defining M-stage separately or when comparing the accuracies of PET/CT colonography with CT + PET. PET/CT colonography affected consecutive therapy decisions in 4 patients (9%; 95% CI, 2.4%-20.4%) compared with conventional staging (CT alone and colonoscopy).
  
  
  CONCLUSIONS
  In this preliminary study, PET/CT colonography is at least equivalent to CT + PET for tumor staging in patients with colorectal cancer. Thus, PET/CT colonography in conjunction with optical colonoscopy may be a suitable concept of tumor staging for patients with colorectal cancer.
authors.affiliation: Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Veit-Haibach
authors.forename: Christiane A
authors.initials: CA
authors.lastname: Kuehle
authors.forename: Thomas
authors.initials: T
authors.lastname: Beyer
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Stergar
authors.forename: Hilmar
authors.initials: H
authors.lastname: Kuehl
authors.forename: Johannes
authors.initials: J
authors.lastname: Schmidt
authors.forename: Gereon
authors.initials: G
authors.lastname: Börsch
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Dahmen
authors.forename: Joerg
authors.initials: J
authors.lastname: Barkhausen
authors.forename: Andreas
authors.initials: A
authors.lastname: Bockisch
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D023881:Colonography, Computed Tomographic; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D049268:Positron-Emission Tomography; D011446:Prospective Studies