title: Value of 11C-choline PET and contrast-enhanced CT for staging of bladder cancer: correlation with histopathologic findings.
abstract: Lymph node involvement is a major prognostic factor in bladder cancer, but the accuracy of conventional imaging modalities for the prediction of regional and distant metastatic diseases is limited. This study was performed to compare the diagnostic accuracies of contrast-enhanced CT and PET with (11)C-choline for the staging of urothelial bladder cancer.
  
  
  METHODS
  Twenty-seven patients (median age, 69.1 y) who had urothelial bladder cancer and who were referred for radical cystectomy and pelvic lymph node dissection (PLND) on the basis of a histologic evaluation after transurethral resection of bladder cancer (TURB) were studied. PET scanning, using 2 multiring whole-body tomographs, was performed 5 min after intravenous injection of approximately 370-500 MBq of (11)C-choline. In addition, conventional bone scintigraphy and contrast-enhanced CT were performed. After imaging, cystectomy and PLND were performed in all patients. Pathologic (11)C-choline uptake that could not be explained by intestinal activity was noted as a positive result. Node positivity was determined by size on CT: nodes measuring more than 1 cm in the long axis were described as being positive for tumor. Histopathologic findings were used as a reference.
  
  
  RESULTS
  The presence of residual bladder cancer (pTa-pT4) was correctly detected in 21 of 25 histologically tumor-positive patients (84%) by CT and in 24 of 25 patients (96%) by (11)C-choline PET. Lymph node involvement was correctly detected in 4 of 8 patients (50%) by CT and in 5 of 8 patients (62%) by (11)C-choline PET. The median size of the 3 nodes with false-negative PET results was 9 mm (range, 6-21 mm), and the median size of the metastatic lesions within the lymph nodes was 3 mm (range, 1-15 mm). CT resulted in 6 (22%) false-positive lymph nodes, whereas none was demonstrated by (11)C-choline PET; these data indicated a significantly higher accuracy of PET than of CT (P < 0.01). Both modalities missed a small peritoneal metastasis verified by histologic evaluation. No positive results were obtained from bone scintigraphy.
  
  
  CONCLUSIONS
  These preliminary data suggest that (11)C-choline PET is comparable to CT for detecting residual bladder cancer after TURB but appears to be superior to CT for the evaluation of potential additional lymph node metastases. (11)C-choline PET should be further evaluated for staging in patients who have bladder cancer and who are scheduled for radical cystectomy.
authors.affiliation: Department of Nuclear Medicine, IBFM-CNR, Scientific Institute H San Raffaele, Milan, Italy. maria.picchio@hsr.it
authors.forename: Maria
authors.initials: M
authors.lastname: Picchio
authors.forename: Uwe
authors.initials: U
authors.lastname: Treiber
authors.forename: Ambros J
authors.initials: AJ
authors.lastname: Beer
authors.forename: Stefan
authors.initials: S
authors.lastname: Metz
authors.forename: Patrick
authors.initials: P
authors.lastname: Bössner
authors.forename: Heiner
authors.initials: H
authors.lastname: van Randenborgh
authors.forename: Roger
authors.initials: R
authors.lastname: Paul
authors.forename: Gregor
authors.initials: G
authors.lastname: Weirich
authors.forename: Michael
authors.initials: M
authors.lastname: Souvatzoglou
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hartung
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.forename: Morand
authors.initials: M
authors.lastname: Piert
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002794:Choline; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed / Q000379:methods*; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D002794:Choline