Diagnostic performance of F-18 FDG PET/CT for mediastinal lymph node staging of non-small cell lung cancer in a tuberculosis endemic country

Objectives The aim of this study was to evaluate the diagnostic performance of pretreatment F-18 FDG PET/CT imaging in mediastinal lymph node staging of patients with non-small cell lung cancer in a tuberculosis endemic country.

Methods Between Aug 2010 and Nov 2012, 96 patients (range, 37-83 y; mean age, 64.5±8.6 y) with non-small cell lung cancer, who underwent F-18 FDG PET/CT for pretreatment staging work-up and followed by lobectomy and thoracic lymphadenectomy were enrolled in this study. The mediastinal lymph node metastases were confirmed histopathologically after thoracic lymphadenectomy. Lymph nodes showing greater F-18 FDG uptake than mediastinum at PET without benign calcification or high attenuation than 70 Hounsfield unit (HU) at unenhanced CT were regarded as metastasis.

Results Mean SUVmax of primary tumor in 39 patients with squamous cell carcinoma (14.3±6.0) was significantly higher than in 57 patients with adenocarcinoma (9.1±6.3,p=0.005). A total of 96 patients with 563 mediastinal node stations were evaluated. Patients with squamous cell carcinoma (17/39, 43.6%) more frequently showed mediastinal lymph node metastasis than patients with adenocarcinoma (12/57, 21.1%). On patient-based analysis, the overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for detecting lymph node metastasis on F-18 FDG PET/CT were 69.8%, 95.4%, 84.3%, 85.2% and 86.8%, respectively. On lesion-based analysis, mean SUVmax of metastatic lymph nodes (8.1±5.6) was significantly higher than of benign lymph nodes (2.5±0.4,p<0.001). The sensitivity, specificity, PPV, NPV and accuracy for detecting lymph node metastasis on F-18 FDG PET/CT were 68.2%, 92.8%, 89.6%, 98.1% and 97.9%, respectively.

Conclusions SUVmax of mediastinal lymph node on the pretreatment F-18 FDG PET/CT revealed excellent specificity for mediastinal lymph node staging and might be used as a noninvasive predictor of patients with non-small cell lung cancer in a tuberculosis endemic country.