Andrea Skanjeti, Abstract Co-Author: Nothing to Disclose

Andrea Billè, Abstract Co-Author: Nothing to Disclose

Vincenzo Arena, Abstract Co-Author: Nothing to Disclose

Luca Errico, Abstract Co-Author: Nothing to Disclose

Maurizio Mancini, Abstract Co-Author: Nothing to Disclose

Ettore Pelosi MD, Presenter: Nothing to Disclose

In patients presenting with localized and clinically resectable Non Small Cell Lung Cancer (NSCLC), intrathoracic lymph node status is the major prognostic factor and determines therapeutic management. Therefore a non invasive exam that could evaluate the lymph-nodes status is useful. Aim of this study is to evaluate the diagnostic accuracy of FDG-PET/CT exam in the mediastinic staging of patients with NSCLC and to explore potential issues of this exam.

287 consecutive patients (mean age 66.1; SD 8.6 yrs) with diagnosis of NSCLC underwent PET/CT scan with FDG (in the same PET center), from 2-3 weeks before surgery. None of the included patients underwent neoadjuvant therapy before surgery. All of them underwent surgery with curative intention. The sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and accuracy (AC) of the exam were evaluated considering as the gold standard the lymph node staging based on hystopathological analysis of tissue specimens. Statistical evaluation of PET/CT results was performed on a per patient and per nodal station basis. Finally, the sensitivity of PET exam was evaluated separately in lymph nodes < 10 mm and ≥ 10 mm.

We evaluated 1851 lymph node stations in 287 patients. Lymph node metastases (133 stations) were found in 88 patients. The disease was correctly staged by FDG-PET exam in 229 out of 287 patients (79.8%), for an amount of 1759 lymph nodes. SE, SP, PPV, NPV and AC on a per patient basis were respectively 63.6%, 86.9%, 68.3%, 84.4%, 79.8%, while on a per nodal station basis were respectively 64.7%, 97.4%, 65.6%, 97.3%, 95%. PET sensitivity in lymph nodes with diameter < 10 mm was 43.2% (32/75), while 88.3% (53/60) in lymph nodes with diameter equal to or greater than 10 mm (p-value < 0,0001).

These data confirm that the main limit of the PET exam with FDG in the mediastinic staging of patients with NSCLC is represented by the lymph node size. In fact when lymph nodes are equal to or greater than 10 mm this exam shows a high sensitivity. To date, technical limits that affect the spatial resolution do not allow the substitution of the mediastinoscopy by the PET exam.

Technical limits that affect the PET spatial resolution, represent an important limitation in the lymph node staging.

Skanjeti, A, Billè, A, Arena, V, Errico, L, Mancini, M, Pelosi, E, Accuracy of FDG-PET/CT in the Mediastinic Staging of Patients with Non Small Cell Lung Cancer (NSCLC).  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8005977.html