BACKGROUND AND OBJECTIVEPositron emission tomography (PET) is used increasingly in staging of non-small cell lung cancer (NSCLC) as a non-invasive tool. However, the role of PET in mediastinal lymphatic staging of NSCLC is not clear. The aim of this study was to demonstrate the efficacy of mediastinoscopy in determining mediastinal lymphatic metastasis in cases of positive PET finding.

METHODSWe performed PET preoperatively in 68 patients with clinically operable NSCLC between 2003 and 2008. Mediastinal lymphatic defined as metastasis by PET (SUV(max) > 2.5) was recorded. Mediastinoscopy being performed initially in all patients. Involvement of mediastinal lymph nodes was verified to compare the sensitivity and specificity of mediastinoscopy and the related PET results.

RESULTSFrom 2003 to 2008, 61 mediastinoscopy were performed. There were 38 men and 23 women, aged from 41 to 81 years (mean 60 years). Localization of the tumor was right lung in 41 patients and left lung in 20 patients. After the operation, 45 patients were demonstrated to have N2 or N3 disease. Ten patients with N3 mediastinal metastasis for chemotherapy, 38 patients with N2 mediastinal metastasis for neuadjuvant chemotherapy while lung resection and systemic mediastinal lymphatic dissection through thoracotomy was performed in the remaining 16 patients with no mediastinal metastasis. The positive prediction value of PET scan was 73.8% (45/61). The sensitivity, specificity, accuracy, positive prediction value and negative prediction value in diagnosis of metastasis of mediastinal lymph nodes were 93.8% (45/48), 100% (13/13), 95.1% (58/61), 100% (45/45), 81.3% (13/16) for mediastinoscopy, respectively.

CONCLUSIONPET results do not provide acceptable accuracy rates. Mediastinoscopy still remains the gold standard for mediastinal staging of NSCLC.