TITLE:
Accuracy of PET/CT with FDG in mediastinal lymph node staging of patients with NSCLC
AUTHORS:
E. Pelosi, A. Billè, A. Skanjeti, V. Arena, F. Ardissone
KEYWORDS:
Integrated PET/CT; Intrathoracic Lymph Node Staging; Lung Cancer
JOURNAL NAME:
Health,
Vol.2 No.3,
March
24,
2010
ABSTRACT: PET/CT and contrast enhancement CT (CECT) are the two fundamental non-invasive exams in the preoperative staging of patients with non small cell lung cancer (NSCLC). In the staging of the mediastinum, recent studies show that PET is more accurate than CECT, with an average sensitivity and specificity of 85 vs. 61% and 90 vs. 79%, respectively. However, thanks to its specificity value of 100%, the gold standard remains the mediastinoscopy. The aim of this study was to evaluate the PET/CT accuracy in the intrathoracic lymph node staging. Three hundred and five consecutive patients with proven or suspected non-small cell lung cancer who had an integrated PET/CT study were retrospectively evaluated. Lymph node staging was pathologically confirmed on tissue specimens obtained at surgery. A medline research of papers on accuracy of integrated PET/CT in lymph node staging was also carried out. In this population of patients, a total of 1972 lymph node stations were evaluated. Integrated PET/CT correctly staged 247 out of 305 patients: 188 of 214 (87.8%) N0 patients, 34 of 40 (85.0%) N1 patients and 25 of 51 (49.0%) N2/N3 patients. PET/CT understaged 32 patients (10.5%) and overstaged 26 patients (8.5%). One hundred and forty-three lymph nodes were proved positive for malignancy. PET/CT correctly identified 89 metastatic lymph node stations. The overall sensitivity, specificity, positive and negative predictive value and accuracy of PET/CT were 64.8%, 87.9%, 69.4%, 85.5%, and 81.0% on a per-patient basis and 62.2%, 97.9%, 69.5%, 97.1%, and 95.3%, on a per-nodal-station basis, respectively. According to nodal size, PET/CT correctly identified 67 out of 77 (87.0%) metastatic lymph node stations with a short-axis di-ameter ≥ 10 mm, and 22 out of 66 (33.3%) metastatic lymph node stations with a short-axis diameter < 10 mm (p<0.001). The incidence of false negative lymph node metastases at PET/CT was higher in patients with adenocarcinoma (42 out of 54). These data are in agreement with the published literature and confirm that integrated PET/CT is more accurate than CT in detecting nodal metastases; however, the PET/CT exam is not enough accurate to substitute mediastinoscopy.