A comparison of radiologic staging with multislice computed tomography to PET/CT and pathological staging in non-small cell lung cancer

The purpose of the study was to compare the staging done with multislice CT (MSCT) to PET/CT and pathological staging in non-small cell lung cancer (NSCLC) cases diagnosed with mediastinoscopy and/or thoracoscopyAmerican Joint Committee on Cancer (AJCC) approved TNM classification was used in a total of 87 cases implicated in the study which consisted of 80 males and 7 females. All of these 87 case stagings were evaluated for N component and 82 cases for T component. Mediastinal and thoracic wall invasion criteria were considered for T classification. In MSCT, nodal diameters of 10 mm and more, in PET/CT, standardized uptake value (SUV) greater than 2.5 were assigned pathologic. Results were compared with pathological findings. Chi-Square and McNemar tests are used for statistical analysisT classification of 66 (80.4%) and 64 (78.0%) cases was not changed in MSCT and PET/CT, respectively, however 8 (9.7%) cases in MSCT and 9 (11%) cases in PET/CT had higher or lower T stages. Sensitivities for T3 staging were 100-91.6% in MSCT and PET/CT respectively, specifity was 91.4%, PPVs were 66.6-64.7%, NPVs were 100%-98.4 and accuracies were 92.6-91.4% respectively. Sensitivity for T4 staging was 76.9%, specifities were 97.1-95.6%, PPVs rates were 83.3-76.9%, NPVs were 95.7-95.6% and accuracies were 93.9-96.2% respectively. Sensitivities for N staging generally were 67.7-66.8% in MSCT and PET/CT respectively, specifity was 86%, PPVs were 73.0-59.3%, NPVs were 87.9-88.5% and accuracy was 84%; when only N2 staging was considered sensitivities were 61.1-66.6%, specifities were 84.0-89.8%, PPVs were 50.0-63.1%, NPVs were 89.2-91.1% and accuracies were 79.3-85.0%, respectively. On the other hand when N2 and N3 were evaluated together, sensitivities were 65.0-70.0%, specifitiy was 92.8%, PPVs were 54.1-56.0%, NPVs were 95.3-95.9% and accuracies were 89.6-90.2%, respectively. Sensitivities for general staging (T+N) were 67.0-63.4%, specifities were 94.3-92.6%, PPVs were 67.0-63.4%, NPVs were 94.3-92.6% and accuracies were calculated as 76.4-74.9%, respectivelyWhen general staging T, general staging N and combined T+N staging were evaluated there was no significant difference between the two methods. CT imaging has crucial importance in evaluation of T component at PET/CT. PET/CT scan is more reliable in N2 and N2+N3 stagings and neither of the scanning methods are reliable for N1 staging. Elevated NPVs indicate that additional testing before thoracoscopy is not essential and decreased PPVs levels indicate that mediastinal sampling is necessary to verify presence of nodal disease.Key Words: NSCLC, Staging, Multislice CT, PET/CT