ORIGINAL ARTICLE Tc-99m depreotide SPECT/CT for lymph node staging of non-small-cell lung cancer Dimitris J. Apostolopoulos • Efstratios N. Koletsis • Trifon Spyridonidis • Anna Paschali • Nikolaos Papandrianos • Eleni Stamou • Pavlos J. Vassilakos • Dimitrios Dougenis Received: 11 January 2014 / Accepted: 7 March 2014 / Published online: 26 March 2014 Ó The Japanese Society of Nuclear Medicine 2014 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 poten- tially operable stage were enrolled and underwent scintig- raphy 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 M1 hilar and 147 M2/M3 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 ulti- mate N-stage and the prediction of surgical disease, diag- nostic 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 circum- stances) and accuracy for M2/M3 stations was substantially improved (88 %). By this quantitative approach, misclas- sifications as to the N-stage and patient operability (25 and 16 %) were considerably less than that of visual Tc-DEPR and diagnostic CT interpretations. Conclusion 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. Quantifica- tion 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. Keywords Non-small-cell lung cancer Á Tc-99m depreotide Á SPECT/CT Á Lymph node staging Introduction Lung cancer is among the leading cause of cancer-related death in men and women both in Europe and US, with cancer mortality rates of 19.8 and 26–29 %, respectively [1, 2]. Despite recent improvements regarding diagnosis and treatment, the overall prognosis for non-small-cell lung cancer (NSCLC) remains poor with 5-year survival rates at D. J. Apostolopoulos (&) Á T. Spyridonidis Á A. Paschali Á N. Papandrianos Á P. J. Vassilakos Department of Nuclear Medicine, University General Hospital of Patras, Medical School, University of Patras, Rion, 26500 Patras, Greece e-mail: dimap@med.upatras.gr E. N. Koletsis Á E. Stamou Á D. Dougenis Department of Cardiothoracic Surgery, University General Hospital of Patras, Medical School, University of Patras, Patras, Greece 123 Ann Nucl Med (2014) 28:463–471 DOI 10.1007/s12149-014-0839-4