The importance of 18F-FDG PET/CT, CT and X-rays in detecting primary stage III A lung cancer and the incidence of extra thoracic metastases.

Lung cancer (LC) has an unfavorable prognosis especially when the disease is extensive at presentation. Accurate staging is therefore needed for treatment planning of these patients. In the present study the role of positron emission tomography/computerized tomography (PET/CT) in the detection of extra thoracic metastases in LC is being evaluated. In all 52 of our patients with stage IIIA or lower of LC disease, a whole body (18)F-FDG PET/CT was performed. All patients were also subjected to general clinical evaluation, chest X-rays and chest contrast enhanced CT (CECT) and were confirmed by histopathology or magnetic resonance imaging or radiology. Incidental extra thoracic malignant lesions were found by (18)F-FDG PET/CT in 9 out of the 52 patients (17.3%). No false positive lesions were found. As for the primary LC diagnosed by fine needle aspiration cytology (FNAC): (18)F-FDG PET/CT diagnosed all 52 cases, CECT detected 46 cases and chest X-rays detected 28 cases. The diagnostic accuracy was 100%, 92% and 53.8% respectively. As for the 9 cases with extrathoracic metastases diagnosed by (18)F-FDG PET/CT they were confirmed: by biopsy 6, by MRI 2 and by X-rays with or without biopsy 2. In conclusion, (18)F-FDG PET/CT had better diagnostic accuracy in diagnosing LC stage IIIA or lower, than CECT or chest X-rays. Extrathoracic metastases were high: 9/52 as diagnosed by (18)F-FDG PET/CT and standardized up take value.