Positron emission tomography/computed tomography for lung cancer staging

Abstract

PET/CT (Positron Emission Tomography/Computed Tomography) is widely used in nodal and metastatic staging of lung cancer patients. To analyze PET/CT detection of metastatic disease in patients with lung cancer. We reviewed retrospectively F18Fluorodeoxyglucose PET/CT scans performed between December 2008 and December 2013. We selected 143 patients aged 30 to 92 years (63% males) with confirmed lung cancer referred for staging, with no previous treatment. We reviewed whole body PET/CT and brain magnetic resonance images. SUVmax (Standardized Uptake Value maximum) of primary pulmonary lesion, hilar/mediastinal nodes, and distant metastases were calculated. Histological types encountered were adenocarcinoma in 55%, squamous-cell in 15%, small-cell in 8%, large-cell in 6% and adeno-squamous in 2%. In 22 cases (15%) histology was not available. Nodal involvement was observed in 60% of patients (44% hilar and 48% mediastinal). Skip metastases (mediastinal involvement without hilum involvement) were encountered in 17% of cases, and were significantly more common among high uptake lung tumors (p < 0.01). Best SUVmax cut-off for node involvement was 4.4 for hilum and 4.0 for mediastinum (sensibility: 86.4%, specificity: 99.8%). Sixty six patients (46.2%) showed distant metastases on PET/CT. The most common metastases were osseous in 22%, adrenal in 16%, hepatic in14%, pulmonary in 14% and cerebral in 12%. PET/CT detected a second unexpected synchronic cancer in eight patients (6%). PET/CT is accurate for nodal staging using an uptake index as SUVmax. Distant metastases are common, especially in bone, adrenal glands and liver.