title: Tc-99m depreotide SPECT/CT for lymph node staging of non-small-cell lung cancer.
abstract: OBJECTIVE
  To investigate the potential role of Tc-99m depreotide (Tc-DEPR) in the preoperative lymph node (N) staging of non-small-cell lung cancer (NSCLC).
  
  
  METHODS
  Sixty-one patients with NSCLC at the potentially operable stage were enrolled and underwent scintigraphy before surgery (n=56) or mediastinoscopy (n=5). Imaging was performed with a hybrid single photon emission computed tomography/computed tomography (SPECT/CT) system. Depreotide uptake in N stations was evaluated visually and semi-quantitatively and compared to histology. Quantification was carried out in attenuation-corrected SPECT slices. Different sites of normal uptake were used as a reference for comparison with lesional uptake. Receiver operating characteristic analysis was employed to identify the most preferable reference area and the cut-off best discriminating disease-free from disease-involved lymph nodes.
  
  
  RESULTS
  With reference to 53 Ν1 hilar and 147 Ν2/Ν3 sampled stations, sensitivity of scintigraphy by visual interpretation was 100 and 94%, specificity 43 and 59% and accuracy 55 and 67%, respectively. No patient was down-staged, but 52% were incorrectly up-staged and 44% were misclassified as inoperable. Compared to scintigraphy, preoperative contrast-enhanced diagnostic CT demonstrated lower sensitivity (36% for hilar and 73% for N2/N3 stations), higher specificity (79 and 75%) and similar accuracy (70 and 75%). Regarding the ultimate N-stage and the prediction of surgical disease, diagnostic CT was wrong in 51 and 34% of cases. Dichotomy of quantitative scintigraphic data by the use of certain N-to-spine ratio cut-offs resulted in a significant increase of specificity (76% for hilar and 89% for N2/N3 stations), while sensitivity remained high (82% in both circumstances) and accuracy for Ν2/Ν3 stations was substantially improved (88%). By this quantitative approach, misclassifications as to the N-stage and patient operability (25 and 16%) were considerably less than that of visual Tc-DEPR and diagnostic CT interpretations.
  
  
  CONCLUSIONS
  Tc-99m depreotide SPECT/CT seems to have a role in the N-staging of NSCLC, mainly because of its high sensitivity and negative predictive value. Quantification of uptake can improve specificity, at a low cost of sensitivity. If F-18 fluoro-deoxyglucose positron emission tomography is not available, this method may be used as a surrogate to conventional staging modalities.
authors.affiliation: Department of Nuclear Medicine, University General Hospital of Patras, Medical School, University of Patras, Rion, 26500, Patras, Greece, dimap@med.upatras.gr.
authors.forename: Dimitris J
authors.initials: DJ
authors.lastname: Apostolopoulos
authors.forename: Efstratios N
authors.initials: EN
authors.lastname: Koletsis
authors.forename: Trifon
authors.initials: T
authors.lastname: Spyridonidis
authors.forename: Anna
authors.initials: A
authors.lastname: Paschali
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Papandrianos
authors.forename: Eleni
authors.initials: E
authors.lastname: Stamou
authors.forename: Pavlos J
authors.initials: PJ
authors.lastname: Vassilakos
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Dougenis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D015609:Organotechnetium Compounds; D057234:Preoperative Period; D013004:Somatostatin / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: D015609:Organotechnetium Compounds; D013004:Somatostatin; C444119:technetium Tc 99m depreotide