title: Laparoscopic extended pelvic lymph node (LN) dissection as validation of the performance of [(11) C]-acetate positron emission tomography/computer tomography in the detection of LN metastasis in intermediate- and high-risk prostate cancer.
abstract: OBJECTIVE
  To evaluate the accuracy of the radiopharmaceutical [(11) C]-acetate combined with positron emission tomography/computer tomography (acetate-PET/CT) in lymph node (LN) staging in newly diagnosed prostate cancer cases. A second aim was to evaluate the potential discriminative properties of acetate-PET/CT in clinical routine.
  
  
  METHODS
  In a prospective comparative study, from July 2010 to June 2013, 53 men with newly histologically diagnosed intermediate- or high-risk prostate cancer underwent acetate-PET/CT investigation at one regional centre before laparoscopic extended pelvic LN dissection (ePLND) at one referral centre. The sensitivity, specificity and accuracy of acetate-PET/CT were calculated. Comparisons were made between true-positive and false-negative PET/CT cases to identify differences in the clinical parameters: PSA level, Gleason status, lymph metastasis burden and size, calculated risk of LN involvement, and curative treatment decisions.
  
  
  RESULTS
  In all, 26 patients had surgically/histologically confirmed LN metastasis (LN+). Acetate-PET/CT was true positive in 10 patients, false positive in one, false negative in 16, and true negative in 26. The individual sensitivity was 38%, specificity 96%, and accuracy 68%. The acetate-PET/CT positive cases had significantly more involved LNs (mean 7.9 vs 2.4, P < 0.001) with larger cancer diameters (14.1 vs 4.9 mm, P = 0.001) and fewer eventually had treatment with curative intent (40% vs 94%, P <0.005), although we lack long-term outcome data.
  
  
  CONCLUSIONS
  Acetate-PET/CT has too low a sensitivity for routine LN staging but the specificity is high. The acetate-PET/CT positive cases have a very high burden of LN spread.
authors.affiliation: Department of Urology, Central Hospital of Karlstad, Karlstad, Sweden.
authors.forename: Georgios
authors.initials: G
authors.lastname: Daouacher
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Catrin
authors.initials: C
authors.lastname: von Below
authors.affiliation: Department of Pathology, Central Hospital of Karlstad, Karlstad, Sweden.
authors.forename: Charlotta
authors.initials: C
authors.lastname: Gestblom
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Ahlström
authors.affiliation: Department of Urology, Central Hospital of Karlstad, Karlstad, Sweden.
authors.forename: Rafael
authors.initials: R
authors.lastname: Grzegorek
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Wassberg
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Jens
authors.initials: J
authors.lastname: Sörensen
authors.affiliation: Department of Urology, Central Hospital of Karlstad, Karlstad, Sweden.
authors.forename: Mauritz
authors.initials: M
authors.lastname: Waldén
mesh_terms: D000085:Acetates; D000368:Aged; D002244:Carbon; D006801:Humans; D010535:Laparoscopy; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000000981:diagnostic imaging; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D019275:Radiopharmaceuticals; D018570:Risk Assessment
chemical_list: D000085:Acetates; D019275:Radiopharmaceuticals; C438206:carbon-11 acetate; D002244:Carbon
keywords: laparoscopy; lymph node staging; lymph nodes; position emission tomography; prostate cancer